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// Algorithm implementation -- C++ -- // Copyright (C) 2001-2018 Free Software Foundation, Inc. // // This file is part of the GNU ISO C++ Library. This library is free // software; you can redistribute it and/or modify it under the // terms of the GNU General Public License as published by the // Free Software Foundation; either version 3, or (at your option) // any later version. // This library is distributed in the hope that it will be useful, // but WITHOUT ANY WARRANTY; without even the implied warranty of // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the // GNU General Public License for more details. // Under Section 7 of GPL version 3, you are granted additional // permissions described in the GCC Runtime Library Exception, version // 3.1, as published by the Free Software Foundation. // You should have received a copy of the GNU General Public License and // a copy of the GCC Runtime Library Exception along with this program; // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see // <http://www.gnu.org/licenses/>. /* * * Copyright (c) 1994 * Hewlett-Packard Company * * Permission to use, copy, modify, distribute and sell this software * and its documentation for any purpose is hereby granted without fee, * provided that the above copyright notice appear in all copies and * that both that copyright notice and this permission notice appear * in supporting documentation. Hewlett-Packard Company makes no * representations about the suitability of this software for any * purpose. It is provided "as is" without express or implied warranty. * * * Copyright (c) 1996 * Silicon Graphics Computer Systems, Inc. * * Permission to use, copy, modify, distribute and sell this software * and its documentation for any purpose is hereby granted without fee, * provided that the above copyright notice appear in all copies and * that both that copyright notice and this permission notice appear * in supporting documentation. Silicon Graphics makes no * representations about the suitability of this software for any * purpose. It is provided "as is" without express or implied warranty. / /* @file bits/stl_algo.h * This is an internal header file, included by other library headers. * Do not attempt to use it directly. @headername{algorithm} / #ifndef _STL_ALGO_H #define _STL_ALGO_H 1 #include <cstdlib> // for rand #include <bits/algorithmfwd.h> #include <bits/stl_heap.h> #include <bits/stl_tempbuf.h> // for _Temporary_buffer #include <bits/predefined_ops.h> #if __cplusplus >= 201103L #include <bits/uniform_int_dist.h> #endif // See concept_check.h for the __glibcxx__requires macros. namespace std _GLIBCXX_VISIBILITY(default) { _GLIBCXX_BEGIN_NAMESPACE_VERSION /// Swaps the median value of __a, __b and __c under __comp to __result template<typename _Iterator, typename _Compare> void __move_median_to_first(_Iterator __result,_Iterator __a, _Iterator __b, _Iterator __c, _Compare __comp) { if (__comp(__a, __b)) { if (__comp(__b, __c)) std::iter_swap(__result, __b); else if (__comp(__a, __c)) std::iter_swap(__result, __c); else std::iter_swap(__result, __a); } else if (__comp(__a, __c)) std::iter_swap(__result, __a); else if (__comp(__b, __c)) std::iter_swap(__result, __c); else std::iter_swap(__result, __b); } /// This is an overload used by find algos for the Input Iterator case. template<typename _InputIterator, typename _Predicate> inline _InputIterator __find_if(_InputIterator __first, _InputIterator __last, _Predicate __pred, input_iterator_tag) { while (__first != __last && !__pred(__first)) ++__first; return __first; } /// This is an overload used by find algos for the RAI case. template<typename _RandomAccessIterator, typename _Predicate> _RandomAccessIterator __find_if(_RandomAccessIterator __first, _RandomAccessIterator __last, _Predicate __pred, random_access_iterator_tag) { typename iterator_traits<_RandomAccessIterator>::difference_type __trip_count = (__last - __first) >> 2; for (; __trip_count > 0; --__trip_count) { if (__pred(__first)) return __first; ++__first; if (__pred(__first)) return __first; ++__first; if (__pred(__first)) return __first; ++__first; if (__pred(__first)) return __first; ++__first; } switch (__last - __first) { case 3: if (__pred(__first)) return __first; ++__first; case 2: if (__pred(__first)) return __first; ++__first; case 1: if (__pred(__first)) return __first; ++__first; case 0: default: return __last; } } template<typename _Iterator, typename _Predicate> inline _Iterator __find_if(_Iterator __first, _Iterator __last, _Predicate __pred) { return __find_if(__first, __last, __pred, std::__iterator_category(__first)); } /// Provided for stable_partition to use. template<typename _InputIterator, typename _Predicate> inline _InputIterator __find_if_not(_InputIterator __first, _InputIterator __last, _Predicate __pred) { return std::__find_if(__first, __last, __gnu_cxx::__ops::__negate(__pred), std::__iterator_category(__first)); } /// Like find_if_not(), but uses and updates a count of the /// remaining range length instead of comparing against an end /// iterator. template<typename _InputIterator, typename _Predicate, typename _Distance> _InputIterator __find_if_not_n(_InputIterator __first, _Distance& __len, _Predicate __pred) { for (; __len; --__len, (void) ++__first) if (!__pred(__first)) break; return __first; } // set_difference // set_intersection // set_symmetric_difference // set_union // for_each // find // find_if // find_first_of // adjacent_find // count // count_if // search template<typename _ForwardIterator1, typename _ForwardIterator2, typename _BinaryPredicate> _ForwardIterator1 __search(_ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2, _ForwardIterator2 __last2, _BinaryPredicate __predicate) { // Test for empty ranges if (__first1 == __last1 \|\| __first2 == __last2) return __first1; // Test for a pattern of length 1. _ForwardIterator2 __p1(__first2); if (++__p1 == __last2) return std::__find_if(__first1, __last1, __gnu_cxx::__ops::__iter_comp_iter(__predicate, __first2)); // General case. _ForwardIterator2 __p; _ForwardIterator1 __current = __first1; for (;;) { __first1 = std::__find_if(__first1, __last1, __gnu_cxx::__ops::__iter_comp_iter(__predicate, __first2)); if (__first1 == __last1) return __last1; __p = __p1; __current = __first1; if (++__current == __last1) return __last1; while (__predicate(__current, __p)) { if (++__p == __last2) return __first1; if (++__current == __last1) return __last1; } ++__first1; } return __first1; } // search_n /** * This is an helper function for search_n overloaded for forward iterators. / template<typename _ForwardIterator, typename _Integer, typename _UnaryPredicate> _ForwardIterator __search_n_aux(_ForwardIterator __first, _ForwardIterator __last, _Integer __count, _UnaryPredicate __unary_pred, std::forward_iterator_tag) { __first = std::__find_if(__first, __last, __unary_pred); while (__first != __last) { typename iterator_traits<_ForwardIterator>::difference_type __n = __count; _ForwardIterator __i = __first; ++__i; while (__i != __last && __n != 1 && __unary_pred(__i)) { ++__i; --__n; } if (__n == 1) return __first; if (__i == __last) return __last; __first = std::__find_if(++__i, __last, __unary_pred); } return __last; } /* * This is an helper function for search_n overloaded for random access * iterators. / template<typename _RandomAccessIter, typename _Integer, typename _UnaryPredicate> _RandomAccessIter __search_n_aux(_RandomAccessIter __first, _RandomAccessIter __last, _Integer __count, _UnaryPredicate __unary_pred, std::random_access_iterator_tag) { typedef typename std::iterator_traits<_RandomAccessIter>::difference_type _DistanceType; _DistanceType __tailSize = __last - __first; _DistanceType __remainder = __count; while (__remainder <= __tailSize) // the main loop... { __first += __remainder; __tailSize -= __remainder; // __first here is always pointing to one past the last element of // next possible match. _RandomAccessIter __backTrack = __first; while (__unary_pred(--__backTrack)) { if (--__remainder == 0) return (__first - __count); // Success } __remainder = __count + 1 - (__first - __backTrack); } return __last; // Failure } template<typename _ForwardIterator, typename _Integer, typename _UnaryPredicate> _ForwardIterator __search_n(_ForwardIterator __first, _ForwardIterator __last, _Integer __count, _UnaryPredicate __unary_pred) { if (__count <= 0) return __first; if (__count == 1) return std::__find_if(__first, __last, __unary_pred); return std::__search_n_aux(__first, __last, __count, __unary_pred, std::__iterator_category(__first)); } // find_end for forward iterators. template<typename _ForwardIterator1, typename _ForwardIterator2, typename _BinaryPredicate> _ForwardIterator1 __find_end(_ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2, _ForwardIterator2 __last2, forward_iterator_tag, forward_iterator_tag, _BinaryPredicate __comp) { if (__first2 == __last2) return __last1; _ForwardIterator1 __result = __last1; while (1) { _ForwardIterator1 __new_result = std::__search(__first1, __last1, __first2, __last2, __comp); if (__new_result == __last1) return __result; else { __result = __new_result; __first1 = __new_result; ++__first1; } } } // find_end for bidirectional iterators (much faster). template<typename _BidirectionalIterator1, typename _BidirectionalIterator2, typename _BinaryPredicate> _BidirectionalIterator1 __find_end(_BidirectionalIterator1 __first1, _BidirectionalIterator1 __last1, _BidirectionalIterator2 __first2, _BidirectionalIterator2 __last2, bidirectional_iterator_tag, bidirectional_iterator_tag, _BinaryPredicate __comp) { // concept requirements __glibcxx_function_requires(_BidirectionalIteratorConcept< _BidirectionalIterator1>) __glibcxx_function_requires(_BidirectionalIteratorConcept< _BidirectionalIterator2>) typedef reverse_iterator<_BidirectionalIterator1> _RevIterator1; typedef reverse_iterator<_BidirectionalIterator2> _RevIterator2; _RevIterator1 __rlast1(__first1); _RevIterator2 __rlast2(__first2); _RevIterator1 __rresult = std::__search(_RevIterator1(__last1), __rlast1, _RevIterator2(__last2), __rlast2, __comp); if (__rresult == __rlast1) return __last1; else { _BidirectionalIterator1 __result = __rresult.base(); std::advance(__result, -std::distance(__first2, __last2)); return __result; } } /* * @brief Find last matching subsequence in a sequence. * @ingroup non_mutating_algorithms * @param __first1 Start of range to search. * @param __last1 End of range to search. * @param __first2 Start of sequence to match. * @param __last2 End of sequence to match. * @return The last iterator @c i in the range * @p [__first1,__last1-(__last2-__first2)) such that @c (i+N) == @p (__first2+N) for each @c N in the range @p [0,__last2-__first2), or @p __last1 if no such iterator exists. * * Searches the range @p [__first1,__last1) for a sub-sequence that * compares equal value-by-value with the sequence given by @p * [__first2,__last2) and returns an iterator to the __first * element of the sub-sequence, or @p __last1 if the sub-sequence * is not found. The sub-sequence will be the last such * subsequence contained in [__first1,__last1). * * Because the sub-sequence must lie completely within the range @p * [__first1,__last1) it must start at a position less than @p * __last1-(__last2-__first2) where @p __last2-__first2 is the * length of the sub-sequence. This means that the returned * iterator @c i will be in the range @p * [__first1,__last1-(__last2-__first2)) / template<typename _ForwardIterator1, typename _ForwardIterator2> inline _ForwardIterator1 find_end(_ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2, _ForwardIterator2 __last2) { // concept requirements __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator1>) __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator2>) __glibcxx_function_requires(_EqualOpConcept< typename iterator_traits<_ForwardIterator1>::value_type, typename iterator_traits<_ForwardIterator2>::value_type>) __glibcxx_requires_valid_range(__first1, __last1); __glibcxx_requires_valid_range(__first2, __last2); return std::__find_end(__first1, __last1, __first2, __last2, std::__iterator_category(__first1), std::__iterator_category(__first2), __gnu_cxx::__ops::__iter_equal_to_iter()); } /* * @brief Find last matching subsequence in a sequence using a predicate. * @ingroup non_mutating_algorithms * @param __first1 Start of range to search. * @param __last1 End of range to search. * @param __first2 Start of sequence to match. * @param __last2 End of sequence to match. * @param __comp The predicate to use. * @return The last iterator @c i in the range @p * [__first1,__last1-(__last2-__first2)) such that @c * predicate((i+N), @p (__first2+N)) is true for each @c N in the range @p [0,__last2-__first2), or @p __last1 if no such iterator * exists. * * Searches the range @p [__first1,__last1) for a sub-sequence that * compares equal value-by-value with the sequence given by @p * [__first2,__last2) using comp as a predicate and returns an * iterator to the first element of the sub-sequence, or @p __last1 * if the sub-sequence is not found. The sub-sequence will be the * last such subsequence contained in [__first,__last1). * * Because the sub-sequence must lie completely within the range @p * [__first1,__last1) it must start at a position less than @p * __last1-(__last2-__first2) where @p __last2-__first2 is the * length of the sub-sequence. This means that the returned * iterator @c i will be in the range @p * [__first1,__last1-(__last2-__first2)) / template<typename _ForwardIterator1, typename _ForwardIterator2, typename _BinaryPredicate> inline _ForwardIterator1 find_end(_ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2, _ForwardIterator2 __last2, _BinaryPredicate __comp) { // concept requirements __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator1>) __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator2>) __glibcxx_function_requires(_BinaryPredicateConcept<_BinaryPredicate, typename iterator_traits<_ForwardIterator1>::value_type, typename iterator_traits<_ForwardIterator2>::value_type>) __glibcxx_requires_valid_range(__first1, __last1); __glibcxx_requires_valid_range(__first2, __last2); return std::__find_end(__first1, __last1, __first2, __last2, std::__iterator_category(__first1), std::__iterator_category(__first2), __gnu_cxx::__ops::__iter_comp_iter(__comp)); } #if __cplusplus >= 201103L /* * @brief Checks that a predicate is true for all the elements * of a sequence. * @ingroup non_mutating_algorithms * @param __first An input iterator. * @param __last An input iterator. * @param __pred A predicate. * @return True if the check is true, false otherwise. * * Returns true if @p __pred is true for each element in the range * @p [__first,__last), and false otherwise. / template<typename _InputIterator, typename _Predicate> inline bool all_of(_InputIterator __first, _InputIterator __last, _Predicate __pred) { return __last == std::find_if_not(__first, __last, __pred); } /* * @brief Checks that a predicate is false for all the elements * of a sequence. * @ingroup non_mutating_algorithms * @param __first An input iterator. * @param __last An input iterator. * @param __pred A predicate. * @return True if the check is true, false otherwise. * * Returns true if @p __pred is false for each element in the range * @p [__first,__last), and false otherwise. / template<typename _InputIterator, typename _Predicate> inline bool none_of(_InputIterator __first, _InputIterator __last, _Predicate __pred) { return __last == _GLIBCXX_STD_A::find_if(__first, __last, __pred); } /* * @brief Checks that a predicate is false for at least an element * of a sequence. * @ingroup non_mutating_algorithms * @param __first An input iterator. * @param __last An input iterator. * @param __pred A predicate. * @return True if the check is true, false otherwise. * * Returns true if an element exists in the range @p * [__first,__last) such that @p __pred is true, and false * otherwise. / template<typename _InputIterator, typename _Predicate> inline bool any_of(_InputIterator __first, _InputIterator __last, _Predicate __pred) { return !std::none_of(__first, __last, __pred); } /* * @brief Find the first element in a sequence for which a * predicate is false. * @ingroup non_mutating_algorithms * @param __first An input iterator. * @param __last An input iterator. * @param __pred A predicate. * @return The first iterator @c i in the range @p [__first,__last) * such that @p __pred(i) is false, or @p __last if no such iterator exists. / template<typename _InputIterator, typename _Predicate> inline _InputIterator find_if_not(_InputIterator __first, _InputIterator __last, _Predicate __pred) { // concept requirements __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>) __glibcxx_function_requires(_UnaryPredicateConcept<_Predicate, typename iterator_traits<_InputIterator>::value_type>) __glibcxx_requires_valid_range(__first, __last); return std::__find_if_not(__first, __last, __gnu_cxx::__ops::__pred_iter(__pred)); } /** * @brief Checks whether the sequence is partitioned. * @ingroup mutating_algorithms * @param __first An input iterator. * @param __last An input iterator. * @param __pred A predicate. * @return True if the range @p [__first,__last) is partioned by @p __pred, * i.e. if all elements that satisfy @p __pred appear before those that * do not. / template<typename _InputIterator, typename _Predicate> inline bool is_partitioned(_InputIterator __first, _InputIterator __last, _Predicate __pred) { __first = std::find_if_not(__first, __last, __pred); if (__first == __last) return true; ++__first; return std::none_of(__first, __last, __pred); } /* * @brief Find the partition point of a partitioned range. * @ingroup mutating_algorithms * @param __first An iterator. * @param __last Another iterator. * @param __pred A predicate. * @return An iterator @p mid such that @p all_of(__first, mid, __pred) * and @p none_of(mid, __last, __pred) are both true. / template<typename _ForwardIterator, typename _Predicate> _ForwardIterator partition_point(_ForwardIterator __first, _ForwardIterator __last, _Predicate __pred) { // concept requirements __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>) __glibcxx_function_requires(_UnaryPredicateConcept<_Predicate, typename iterator_traits<_ForwardIterator>::value_type>) // A specific debug-mode test will be necessary... __glibcxx_requires_valid_range(__first, __last); typedef typename iterator_traits<_ForwardIterator>::difference_type _DistanceType; _DistanceType __len = std::distance(__first, __last); _DistanceType __half; _ForwardIterator __middle; while (__len > 0) { __half = __len >> 1; __middle = __first; std::advance(__middle, __half); if (__pred(__middle)) { __first = __middle; ++__first; __len = __len - __half - 1; } else __len = __half; } return __first; } #endif template<typename _InputIterator, typename _OutputIterator, typename _Predicate> _OutputIterator __remove_copy_if(_InputIterator __first, _InputIterator __last, _OutputIterator __result, _Predicate __pred) { for (; __first != __last; ++__first) if (!__pred(__first)) { __result = __first; ++__result; } return __result; } /** * @brief Copy a sequence, removing elements of a given value. * @ingroup mutating_algorithms * @param __first An input iterator. * @param __last An input iterator. * @param __result An output iterator. * @param __value The value to be removed. * @return An iterator designating the end of the resulting sequence. * * Copies each element in the range @p [__first,__last) not equal * to @p __value to the range beginning at @p __result. * remove_copy() is stable, so the relative order of elements that * are copied is unchanged. / template<typename _InputIterator, typename _OutputIterator, typename _Tp> inline _OutputIterator remove_copy(_InputIterator __first, _InputIterator __last, _OutputIterator __result, const _Tp& __value) { // concept requirements __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>) __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator, typename iterator_traits<_InputIterator>::value_type>) __glibcxx_function_requires(_EqualOpConcept< typename iterator_traits<_InputIterator>::value_type, _Tp>) __glibcxx_requires_valid_range(__first, __last); return std::__remove_copy_if(__first, __last, __result, __gnu_cxx::__ops::__iter_equals_val(__value)); } /* * @brief Copy a sequence, removing elements for which a predicate is true. * @ingroup mutating_algorithms * @param __first An input iterator. * @param __last An input iterator. * @param __result An output iterator. * @param __pred A predicate. * @return An iterator designating the end of the resulting sequence. * * Copies each element in the range @p [__first,__last) for which * @p __pred returns false to the range beginning at @p __result. * * remove_copy_if() is stable, so the relative order of elements that are * copied is unchanged. / template<typename _InputIterator, typename _OutputIterator, typename _Predicate> inline _OutputIterator remove_copy_if(_InputIterator __first, _InputIterator __last, _OutputIterator __result, _Predicate __pred) { // concept requirements __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>) __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator, typename iterator_traits<_InputIterator>::value_type>) __glibcxx_function_requires(_UnaryPredicateConcept<_Predicate, typename iterator_traits<_InputIterator>::value_type>) __glibcxx_requires_valid_range(__first, __last); return std::__remove_copy_if(__first, __last, __result, __gnu_cxx::__ops::__pred_iter(__pred)); } #if __cplusplus >= 201103L /* * @brief Copy the elements of a sequence for which a predicate is true. * @ingroup mutating_algorithms * @param __first An input iterator. * @param __last An input iterator. * @param __result An output iterator. * @param __pred A predicate. * @return An iterator designating the end of the resulting sequence. * * Copies each element in the range @p [__first,__last) for which * @p __pred returns true to the range beginning at @p __result. * * copy_if() is stable, so the relative order of elements that are * copied is unchanged. / template<typename _InputIterator, typename _OutputIterator, typename _Predicate> _OutputIterator copy_if(_InputIterator __first, _InputIterator __last, _OutputIterator __result, _Predicate __pred) { // concept requirements __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>) __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator, typename iterator_traits<_InputIterator>::value_type>) __glibcxx_function_requires(_UnaryPredicateConcept<_Predicate, typename iterator_traits<_InputIterator>::value_type>) __glibcxx_requires_valid_range(__first, __last); for (; __first != __last; ++__first) if (__pred(__first)) { __result = __first; ++__result; } return __result; } template<typename _InputIterator, typename _Size, typename _OutputIterator> _OutputIterator __copy_n(_InputIterator __first, _Size __n, _OutputIterator __result, input_iterator_tag) { if (__n > 0) { while (true) { __result = __first; ++__result; if (--__n > 0) ++__first; else break; } } return __result; } template<typename _RandomAccessIterator, typename _Size, typename _OutputIterator> inline _OutputIterator __copy_n(_RandomAccessIterator __first, _Size __n, _OutputIterator __result, random_access_iterator_tag) { return std::copy(__first, __first + __n, __result); } /** * @brief Copies the range [first,first+n) into [result,result+n). * @ingroup mutating_algorithms * @param __first An input iterator. * @param __n The number of elements to copy. * @param __result An output iterator. * @return result+n. * * This inline function will boil down to a call to @c memmove whenever * possible. Failing that, if random access iterators are passed, then the * loop count will be known (and therefore a candidate for compiler * optimizations such as unrolling). / template<typename _InputIterator, typename _Size, typename _OutputIterator> inline _OutputIterator copy_n(_InputIterator __first, _Size __n, _OutputIterator __result) { // concept requirements __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>) __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator, typename iterator_traits<_InputIterator>::value_type>) return std::__copy_n(__first, __n, __result, std::__iterator_category(__first)); } /* * @brief Copy the elements of a sequence to separate output sequences * depending on the truth value of a predicate. * @ingroup mutating_algorithms * @param __first An input iterator. * @param __last An input iterator. * @param __out_true An output iterator. * @param __out_false An output iterator. * @param __pred A predicate. * @return A pair designating the ends of the resulting sequences. * * Copies each element in the range @p [__first,__last) for which * @p __pred returns true to the range beginning at @p out_true * and each element for which @p __pred returns false to @p __out_false. / template<typename _InputIterator, typename _OutputIterator1, typename _OutputIterator2, typename _Predicate> pair<_OutputIterator1, _OutputIterator2> partition_copy(_InputIterator __first, _InputIterator __last, _OutputIterator1 __out_true, _OutputIterator2 __out_false, _Predicate __pred) { // concept requirements __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>) __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator1, typename iterator_traits<_InputIterator>::value_type>) __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator2, typename iterator_traits<_InputIterator>::value_type>) __glibcxx_function_requires(_UnaryPredicateConcept<_Predicate, typename iterator_traits<_InputIterator>::value_type>) __glibcxx_requires_valid_range(__first, __last); for (; __first != __last; ++__first) if (__pred(__first)) { __out_true = __first; ++__out_true; } else { __out_false = __first; ++__out_false; } return pair<_OutputIterator1, _OutputIterator2>(__out_true, __out_false); } #endif template<typename _ForwardIterator, typename _Predicate> _ForwardIterator __remove_if(_ForwardIterator __first, _ForwardIterator __last, _Predicate __pred) { __first = std::__find_if(__first, __last, __pred); if (__first == __last) return __first; _ForwardIterator __result = __first; ++__first; for (; __first != __last; ++__first) if (!__pred(__first)) { __result = _GLIBCXX_MOVE(__first); ++__result; } return __result; } /** * @brief Remove elements from a sequence. * @ingroup mutating_algorithms * @param __first An input iterator. * @param __last An input iterator. * @param __value The value to be removed. * @return An iterator designating the end of the resulting sequence. * * All elements equal to @p __value are removed from the range * @p [__first,__last). * * remove() is stable, so the relative order of elements that are * not removed is unchanged. * * Elements between the end of the resulting sequence and @p __last * are still present, but their value is unspecified. / template<typename _ForwardIterator, typename _Tp> inline _ForwardIterator remove(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value) { // concept requirements __glibcxx_function_requires(_Mutable_ForwardIteratorConcept< _ForwardIterator>) __glibcxx_function_requires(_EqualOpConcept< typename iterator_traits<_ForwardIterator>::value_type, _Tp>) __glibcxx_requires_valid_range(__first, __last); return std::__remove_if(__first, __last, __gnu_cxx::__ops::__iter_equals_val(__value)); } /* * @brief Remove elements from a sequence using a predicate. * @ingroup mutating_algorithms * @param __first A forward iterator. * @param __last A forward iterator. * @param __pred A predicate. * @return An iterator designating the end of the resulting sequence. * * All elements for which @p __pred returns true are removed from the range * @p [__first,__last). * * remove_if() is stable, so the relative order of elements that are * not removed is unchanged. * * Elements between the end of the resulting sequence and @p __last * are still present, but their value is unspecified. / template<typename _ForwardIterator, typename _Predicate> inline _ForwardIterator remove_if(_ForwardIterator __first, _ForwardIterator __last, _Predicate __pred) { // concept requirements __glibcxx_function_requires(_Mutable_ForwardIteratorConcept< _ForwardIterator>) __glibcxx_function_requires(_UnaryPredicateConcept<_Predicate, typename iterator_traits<_ForwardIterator>::value_type>) __glibcxx_requires_valid_range(__first, __last); return std::__remove_if(__first, __last, __gnu_cxx::__ops::__pred_iter(__pred)); } template<typename _ForwardIterator, typename _BinaryPredicate> _ForwardIterator __adjacent_find(_ForwardIterator __first, _ForwardIterator __last, _BinaryPredicate __binary_pred) { if (__first == __last) return __last; _ForwardIterator __next = __first; while (++__next != __last) { if (__binary_pred(__first, __next)) return __first; __first = __next; } return __last; } template<typename _ForwardIterator, typename _BinaryPredicate> _ForwardIterator __unique(_ForwardIterator __first, _ForwardIterator __last, _BinaryPredicate __binary_pred) { // Skip the beginning, if already unique. __first = std::__adjacent_find(__first, __last, __binary_pred); if (__first == __last) return __last; // Do the real copy work. _ForwardIterator __dest = __first; ++__first; while (++__first != __last) if (!__binary_pred(__dest, __first)) ++__dest = _GLIBCXX_MOVE(__first); return ++__dest; } /* * @brief Remove consecutive duplicate values from a sequence. * @ingroup mutating_algorithms * @param __first A forward iterator. * @param __last A forward iterator. * @return An iterator designating the end of the resulting sequence. * * Removes all but the first element from each group of consecutive * values that compare equal. * unique() is stable, so the relative order of elements that are * not removed is unchanged. * Elements between the end of the resulting sequence and @p __last * are still present, but their value is unspecified. / template<typename _ForwardIterator> inline _ForwardIterator unique(_ForwardIterator __first, _ForwardIterator __last) { // concept requirements __glibcxx_function_requires(_Mutable_ForwardIteratorConcept< _ForwardIterator>) __glibcxx_function_requires(_EqualityComparableConcept< typename iterator_traits<_ForwardIterator>::value_type>) __glibcxx_requires_valid_range(__first, __last); return std::__unique(__first, __last, __gnu_cxx::__ops::__iter_equal_to_iter()); } /* * @brief Remove consecutive values from a sequence using a predicate. * @ingroup mutating_algorithms * @param __first A forward iterator. * @param __last A forward iterator. * @param __binary_pred A binary predicate. * @return An iterator designating the end of the resulting sequence. * * Removes all but the first element from each group of consecutive * values for which @p __binary_pred returns true. * unique() is stable, so the relative order of elements that are * not removed is unchanged. * Elements between the end of the resulting sequence and @p __last * are still present, but their value is unspecified. / template<typename _ForwardIterator, typename _BinaryPredicate> inline _ForwardIterator unique(_ForwardIterator __first, _ForwardIterator __last, _BinaryPredicate __binary_pred) { // concept requirements __glibcxx_function_requires(_Mutable_ForwardIteratorConcept< _ForwardIterator>) __glibcxx_function_requires(_BinaryPredicateConcept<_BinaryPredicate, typename iterator_traits<_ForwardIterator>::value_type, typename iterator_traits<_ForwardIterator>::value_type>) __glibcxx_requires_valid_range(__first, __last); return std::__unique(__first, __last, __gnu_cxx::__ops::__iter_comp_iter(__binary_pred)); } /* * This is an uglified * unique_copy(_InputIterator, _InputIterator, _OutputIterator, * _BinaryPredicate) * overloaded for forward iterators and output iterator as result. / template<typename _ForwardIterator, typename _OutputIterator, typename _BinaryPredicate> _OutputIterator __unique_copy(_ForwardIterator __first, _ForwardIterator __last, _OutputIterator __result, _BinaryPredicate __binary_pred, forward_iterator_tag, output_iterator_tag) { // concept requirements -- iterators already checked __glibcxx_function_requires(_BinaryPredicateConcept<_BinaryPredicate, typename iterator_traits<_ForwardIterator>::value_type, typename iterator_traits<_ForwardIterator>::value_type>) _ForwardIterator __next = __first; __result = __first; while (++__next != __last) if (!__binary_pred(__first, __next)) { __first = __next; ++__result = __first; } return ++__result; } /* * This is an uglified * unique_copy(_InputIterator, _InputIterator, _OutputIterator, * _BinaryPredicate) * overloaded for input iterators and output iterator as result. / template<typename _InputIterator, typename _OutputIterator, typename _BinaryPredicate> _OutputIterator __unique_copy(_InputIterator __first, _InputIterator __last, _OutputIterator __result, _BinaryPredicate __binary_pred, input_iterator_tag, output_iterator_tag) { // concept requirements -- iterators already checked __glibcxx_function_requires(_BinaryPredicateConcept<_BinaryPredicate, typename iterator_traits<_InputIterator>::value_type, typename iterator_traits<_InputIterator>::value_type>) typename iterator_traits<_InputIterator>::value_type __value = __first; __decltype(__gnu_cxx::__ops::__iter_comp_val(__binary_pred)) __rebound_pred = __gnu_cxx::__ops::__iter_comp_val(__binary_pred); __result = __value; while (++__first != __last) if (!__rebound_pred(__first, __value)) { __value = __first; ++__result = __value; } return ++__result; } /* * This is an uglified * unique_copy(_InputIterator, _InputIterator, _OutputIterator, * _BinaryPredicate) * overloaded for input iterators and forward iterator as result. / template<typename _InputIterator, typename _ForwardIterator, typename _BinaryPredicate> _ForwardIterator __unique_copy(_InputIterator __first, _InputIterator __last, _ForwardIterator __result, _BinaryPredicate __binary_pred, input_iterator_tag, forward_iterator_tag) { // concept requirements -- iterators already checked __glibcxx_function_requires(_BinaryPredicateConcept<_BinaryPredicate, typename iterator_traits<_ForwardIterator>::value_type, typename iterator_traits<_InputIterator>::value_type>) __result = __first; while (++__first != __last) if (!__binary_pred(__result, __first)) ++__result = __first; return ++__result; } /* * This is an uglified reverse(_BidirectionalIterator, * _BidirectionalIterator) * overloaded for bidirectional iterators. / template<typename _BidirectionalIterator> void __reverse(_BidirectionalIterator __first, _BidirectionalIterator __last, bidirectional_iterator_tag) { while (true) if (__first == __last \|\| __first == --__last) return; else { std::iter_swap(__first, __last); ++__first; } } /* * This is an uglified reverse(_BidirectionalIterator, * _BidirectionalIterator) * overloaded for random access iterators. / template<typename _RandomAccessIterator> void __reverse(_RandomAccessIterator __first, _RandomAccessIterator __last, random_access_iterator_tag) { if (__first == __last) return; --__last; while (__first < __last) { std::iter_swap(__first, __last); ++__first; --__last; } } /* * @brief Reverse a sequence. * @ingroup mutating_algorithms * @param __first A bidirectional iterator. * @param __last A bidirectional iterator. * @return reverse() returns no value. * * Reverses the order of the elements in the range @p [__first,__last), * so that the first element becomes the last etc. * For every @c i such that @p 0<=i<=(__last-__first)/2), @p reverse() * swaps @p (__first+i) and @p (__last-(i+1)) / template<typename _BidirectionalIterator> inline void reverse(_BidirectionalIterator __first, _BidirectionalIterator __last) { // concept requirements __glibcxx_function_requires(_Mutable_BidirectionalIteratorConcept< _BidirectionalIterator>) __glibcxx_requires_valid_range(__first, __last); std::__reverse(__first, __last, std::__iterator_category(__first)); } /* * @brief Copy a sequence, reversing its elements. * @ingroup mutating_algorithms * @param __first A bidirectional iterator. * @param __last A bidirectional iterator. * @param __result An output iterator. * @return An iterator designating the end of the resulting sequence. * * Copies the elements in the range @p [__first,__last) to the * range @p [__result,__result+(__last-__first)) such that the * order of the elements is reversed. For every @c i such that @p * 0<=i<=(__last-__first), @p reverse_copy() performs the * assignment @p (__result+(__last-__first)-1-i) = (__first+i). * The ranges @p [__first,__last) and @p * [__result,__result+(__last-__first)) must not overlap. / template<typename _BidirectionalIterator, typename _OutputIterator> _OutputIterator reverse_copy(_BidirectionalIterator __first, _BidirectionalIterator __last, _OutputIterator __result) { // concept requirements __glibcxx_function_requires(_BidirectionalIteratorConcept< _BidirectionalIterator>) __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator, typename iterator_traits<_BidirectionalIterator>::value_type>) __glibcxx_requires_valid_range(__first, __last); while (__first != __last) { --__last; __result = __last; ++__result; } return __result; } /* * This is a helper function for the rotate algorithm specialized on RAIs. * It returns the greatest common divisor of two integer values. / template<typename _EuclideanRingElement> _EuclideanRingElement __gcd(_EuclideanRingElement __m, _EuclideanRingElement __n) { while (__n != 0) { _EuclideanRingElement __t = __m % __n; __m = __n; __n = __t; } return __m; } inline namespace _V2 { /// This is a helper function for the rotate algorithm. template<typename _ForwardIterator> _ForwardIterator __rotate(_ForwardIterator __first, _ForwardIterator __middle, _ForwardIterator __last, forward_iterator_tag) { if (__first == __middle) return __last; else if (__last == __middle) return __first; _ForwardIterator __first2 = __middle; do { std::iter_swap(__first, __first2); ++__first; ++__first2; if (__first == __middle) __middle = __first2; } while (__first2 != __last); _ForwardIterator __ret = __first; __first2 = __middle; while (__first2 != __last) { std::iter_swap(__first, __first2); ++__first; ++__first2; if (__first == __middle) __middle = __first2; else if (__first2 == __last) __first2 = __middle; } return __ret; } /// This is a helper function for the rotate algorithm. template<typename _BidirectionalIterator> _BidirectionalIterator __rotate(_BidirectionalIterator __first, _BidirectionalIterator __middle, _BidirectionalIterator __last, bidirectional_iterator_tag) { // concept requirements __glibcxx_function_requires(_Mutable_BidirectionalIteratorConcept< _BidirectionalIterator>) if (__first == __middle) return __last; else if (__last == __middle) return __first; std::__reverse(__first, __middle, bidirectional_iterator_tag()); std::__reverse(__middle, __last, bidirectional_iterator_tag()); while (__first != __middle && __middle != __last) { std::iter_swap(__first, --__last); ++__first; } if (__first == __middle) { std::__reverse(__middle, __last, bidirectional_iterator_tag()); return __last; } else { std::__reverse(__first, __middle, bidirectional_iterator_tag()); return __first; } } /// This is a helper function for the rotate algorithm. template<typename _RandomAccessIterator> _RandomAccessIterator __rotate(_RandomAccessIterator __first, _RandomAccessIterator __middle, _RandomAccessIterator __last, random_access_iterator_tag) { // concept requirements __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept< _RandomAccessIterator>) if (__first == __middle) return __last; else if (__last == __middle) return __first; typedef typename iterator_traits<_RandomAccessIterator>::difference_type _Distance; typedef typename iterator_traits<_RandomAccessIterator>::value_type _ValueType; _Distance __n = __last - __first; _Distance __k = __middle - __first; if (__k == __n - __k) { std::swap_ranges(__first, __middle, __middle); return __middle; } _RandomAccessIterator __p = __first; _RandomAccessIterator __ret = __first + (__last - __middle); for (;;) { if (__k < __n - __k) { if (__is_pod(_ValueType) && __k == 1) { _ValueType __t = _GLIBCXX_MOVE(__p); _GLIBCXX_MOVE3(__p + 1, __p + __n, __p); (__p + __n - 1) = _GLIBCXX_MOVE(__t); return __ret; } _RandomAccessIterator __q = __p + __k; for (_Distance __i = 0; __i < __n - __k; ++ __i) { std::iter_swap(__p, __q); ++__p; ++__q; } __n %= __k; if (__n == 0) return __ret; std::swap(__n, __k); __k = __n - __k; } else { __k = __n - __k; if (__is_pod(_ValueType) && __k == 1) { _ValueType __t = _GLIBCXX_MOVE((__p + __n - 1)); _GLIBCXX_MOVE_BACKWARD3(__p, __p + __n - 1, __p + __n); __p = _GLIBCXX_MOVE(__t); return __ret; } _RandomAccessIterator __q = __p + __n; __p = __q - __k; for (_Distance __i = 0; __i < __n - __k; ++ __i) { --__p; --__q; std::iter_swap(__p, __q); } __n %= __k; if (__n == 0) return __ret; std::swap(__n, __k); } } } // _GLIBCXX_RESOLVE_LIB_DEFECTS // DR 488. rotate throws away useful information /* * @brief Rotate the elements of a sequence. * @ingroup mutating_algorithms * @param __first A forward iterator. * @param __middle A forward iterator. * @param __last A forward iterator. * @return first + (last - middle). * * Rotates the elements of the range @p [__first,__last) by * @p (__middle - __first) positions so that the element at @p __middle * is moved to @p __first, the element at @p __middle+1 is moved to * @p __first+1 and so on for each element in the range * @p [__first,__last). * * This effectively swaps the ranges @p [__first,__middle) and * @p [__middle,__last). * * Performs * @p (__first+(n+(__last-__middle))%(__last-__first))=(__first+n) * for each @p n in the range @p [0,__last-__first). / template<typename _ForwardIterator> inline _ForwardIterator rotate(_ForwardIterator __first, _ForwardIterator __middle, _ForwardIterator __last) { // concept requirements __glibcxx_function_requires(_Mutable_ForwardIteratorConcept< _ForwardIterator>) __glibcxx_requires_valid_range(__first, __middle); __glibcxx_requires_valid_range(__middle, __last); return std::__rotate(__first, __middle, __last, std::__iterator_category(__first)); } } // namespace _V2 /* * @brief Copy a sequence, rotating its elements. * @ingroup mutating_algorithms * @param __first A forward iterator. * @param __middle A forward iterator. * @param __last A forward iterator. * @param __result An output iterator. * @return An iterator designating the end of the resulting sequence. * * Copies the elements of the range @p [__first,__last) to the * range beginning at @result, rotating the copied elements by * @p (__middle-__first) positions so that the element at @p __middle * is moved to @p __result, the element at @p __middle+1 is moved * to @p __result+1 and so on for each element in the range @p * [__first,__last). * * Performs * @p (__result+(n+(__last-__middle))%(__last-__first))=(__first+n) * for each @p n in the range @p [0,__last-__first). / template<typename _ForwardIterator, typename _OutputIterator> inline _OutputIterator rotate_copy(_ForwardIterator __first, _ForwardIterator __middle, _ForwardIterator __last, _OutputIterator __result) { // concept requirements __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>) __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator, typename iterator_traits<_ForwardIterator>::value_type>) __glibcxx_requires_valid_range(__first, __middle); __glibcxx_requires_valid_range(__middle, __last); return std::copy(__first, __middle, std::copy(__middle, __last, __result)); } /// This is a helper function... template<typename _ForwardIterator, typename _Predicate> _ForwardIterator __partition(_ForwardIterator __first, _ForwardIterator __last, _Predicate __pred, forward_iterator_tag) { if (__first == __last) return __first; while (__pred(__first)) if (++__first == __last) return __first; _ForwardIterator __next = __first; while (++__next != __last) if (__pred(__next)) { std::iter_swap(__first, __next); ++__first; } return __first; } /// This is a helper function... template<typename _BidirectionalIterator, typename _Predicate> _BidirectionalIterator __partition(_BidirectionalIterator __first, _BidirectionalIterator __last, _Predicate __pred, bidirectional_iterator_tag) { while (true) { while (true) if (__first == __last) return __first; else if (__pred(__first)) ++__first; else break; --__last; while (true) if (__first == __last) return __first; else if (!bool(__pred(__last))) --__last; else break; std::iter_swap(__first, __last); ++__first; } } // partition /// This is a helper function... /// Requires __first != __last and !__pred(__first) /// and __len == distance(__first, __last). /// /// !__pred(__first) allows us to guarantee that we don't /// move-assign an element onto itself. template<typename _ForwardIterator, typename _Pointer, typename _Predicate, typename _Distance> _ForwardIterator __stable_partition_adaptive(_ForwardIterator __first, _ForwardIterator __last, _Predicate __pred, _Distance __len, _Pointer __buffer, _Distance __buffer_size) { if (__len == 1) return __first; if (__len <= __buffer_size) { _ForwardIterator __result1 = __first; _Pointer __result2 = __buffer; // The precondition guarantees that !__pred(__first), so // move that element to the buffer before starting the loop. // This ensures that we only call __pred once per element. __result2 = _GLIBCXX_MOVE(__first); ++__result2; ++__first; for (; __first != __last; ++__first) if (__pred(__first)) { __result1 = _GLIBCXX_MOVE(__first); ++__result1; } else { __result2 = _GLIBCXX_MOVE(__first); ++__result2; } _GLIBCXX_MOVE3(__buffer, __result2, __result1); return __result1; } _ForwardIterator __middle = __first; std::advance(__middle, __len / 2); _ForwardIterator __left_split = std::__stable_partition_adaptive(__first, __middle, __pred, __len / 2, __buffer, __buffer_size); // Advance past true-predicate values to satisfy this // function's preconditions. _Distance __right_len = __len - __len / 2; _ForwardIterator __right_split = std::__find_if_not_n(__middle, __right_len, __pred); if (__right_len) __right_split = std::__stable_partition_adaptive(__right_split, __last, __pred, __right_len, __buffer, __buffer_size); std::rotate(__left_split, __middle, __right_split); std::advance(__left_split, std::distance(__middle, __right_split)); return __left_split; } template<typename _ForwardIterator, typename _Predicate> _ForwardIterator __stable_partition(_ForwardIterator __first, _ForwardIterator __last, _Predicate __pred) { __first = std::__find_if_not(__first, __last, __pred); if (__first == __last) return __first; typedef typename iterator_traits<_ForwardIterator>::value_type _ValueType; typedef typename iterator_traits<_ForwardIterator>::difference_type _DistanceType; _Temporary_buffer<_ForwardIterator, _ValueType> __buf(__first, __last); return std::__stable_partition_adaptive(__first, __last, __pred, _DistanceType(__buf.requested_size()), __buf.begin(), _DistanceType(__buf.size())); } /* * @brief Move elements for which a predicate is true to the beginning * of a sequence, preserving relative ordering. * @ingroup mutating_algorithms * @param __first A forward iterator. * @param __last A forward iterator. * @param __pred A predicate functor. * @return An iterator @p middle such that @p __pred(i) is true for each * iterator @p i in the range @p [first,middle) and false for each @p i * in the range @p [middle,last). * * Performs the same function as @p partition() with the additional * guarantee that the relative ordering of elements in each group is * preserved, so any two elements @p x and @p y in the range * @p [__first,__last) such that @p __pred(x)==__pred(y) will have the same * relative ordering after calling @p stable_partition(). / template<typename _ForwardIterator, typename _Predicate> inline _ForwardIterator stable_partition(_ForwardIterator __first, _ForwardIterator __last, _Predicate __pred) { // concept requirements __glibcxx_function_requires(_Mutable_ForwardIteratorConcept< _ForwardIterator>) __glibcxx_function_requires(_UnaryPredicateConcept<_Predicate, typename iterator_traits<_ForwardIterator>::value_type>) __glibcxx_requires_valid_range(__first, __last); return std::__stable_partition(__first, __last, __gnu_cxx::__ops::__pred_iter(__pred)); } /// This is a helper function for the sort routines. template<typename _RandomAccessIterator, typename _Compare> void __heap_select(_RandomAccessIterator __first, _RandomAccessIterator __middle, _RandomAccessIterator __last, _Compare __comp) { std::__make_heap(__first, __middle, __comp); for (_RandomAccessIterator __i = __middle; __i < __last; ++__i) if (__comp(__i, __first)) std::__pop_heap(__first, __middle, __i, __comp); } // partial_sort template<typename _InputIterator, typename _RandomAccessIterator, typename _Compare> _RandomAccessIterator __partial_sort_copy(_InputIterator __first, _InputIterator __last, _RandomAccessIterator __result_first, _RandomAccessIterator __result_last, _Compare __comp) { typedef typename iterator_traits<_InputIterator>::value_type _InputValueType; typedef iterator_traits<_RandomAccessIterator> _RItTraits; typedef typename _RItTraits::difference_type _DistanceType; if (__result_first == __result_last) return __result_last; _RandomAccessIterator __result_real_last = __result_first; while (__first != __last && __result_real_last != __result_last) { __result_real_last = __first; ++__result_real_last; ++__first; } std::__make_heap(__result_first, __result_real_last, __comp); while (__first != __last) { if (__comp(__first, __result_first)) std::__adjust_heap(__result_first, _DistanceType(0), _DistanceType(__result_real_last - __result_first), _InputValueType(__first), __comp); ++__first; } std::__sort_heap(__result_first, __result_real_last, __comp); return __result_real_last; } /** * @brief Copy the smallest elements of a sequence. * @ingroup sorting_algorithms * @param __first An iterator. * @param __last Another iterator. * @param __result_first A random-access iterator. * @param __result_last Another random-access iterator. * @return An iterator indicating the end of the resulting sequence. * * Copies and sorts the smallest N values from the range @p [__first,__last) * to the range beginning at @p __result_first, where the number of * elements to be copied, @p N, is the smaller of @p (__last-__first) and * @p (__result_last-__result_first). * After the sort if @e i and @e j are iterators in the range * @p [__result_first,__result_first+N) such that i precedes j then * j<i is false. * The value returned is @p __result_first+N. / template<typename _InputIterator, typename _RandomAccessIterator> inline _RandomAccessIterator partial_sort_copy(_InputIterator __first, _InputIterator __last, _RandomAccessIterator __result_first, _RandomAccessIterator __result_last) { #ifdef _GLIBCXX_CONCEPT_CHECKS typedef typename iterator_traits<_InputIterator>::value_type _InputValueType; typedef typename iterator_traits<_RandomAccessIterator>::value_type _OutputValueType; #endif // concept requirements __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>) __glibcxx_function_requires(_ConvertibleConcept<_InputValueType, _OutputValueType>) __glibcxx_function_requires(_LessThanOpConcept<_InputValueType, _OutputValueType>) __glibcxx_function_requires(_LessThanComparableConcept<_OutputValueType>) __glibcxx_requires_valid_range(__first, __last); __glibcxx_requires_irreflexive(__first, __last); __glibcxx_requires_valid_range(__result_first, __result_last); return std::__partial_sort_copy(__first, __last, __result_first, __result_last, __gnu_cxx::__ops::__iter_less_iter()); } /* * @brief Copy the smallest elements of a sequence using a predicate for * comparison. * @ingroup sorting_algorithms * @param __first An input iterator. * @param __last Another input iterator. * @param __result_first A random-access iterator. * @param __result_last Another random-access iterator. * @param __comp A comparison functor. * @return An iterator indicating the end of the resulting sequence. * * Copies and sorts the smallest N values from the range @p [__first,__last) * to the range beginning at @p result_first, where the number of * elements to be copied, @p N, is the smaller of @p (__last-__first) and * @p (__result_last-__result_first). * After the sort if @e i and @e j are iterators in the range * @p [__result_first,__result_first+N) such that i precedes j then * @p __comp(j,i) is false. * The value returned is @p __result_first+N. / template<typename _InputIterator, typename _RandomAccessIterator, typename _Compare> inline _RandomAccessIterator partial_sort_copy(_InputIterator __first, _InputIterator __last, _RandomAccessIterator __result_first, _RandomAccessIterator __result_last, _Compare __comp) { #ifdef _GLIBCXX_CONCEPT_CHECKS typedef typename iterator_traits<_InputIterator>::value_type _InputValueType; typedef typename iterator_traits<_RandomAccessIterator>::value_type _OutputValueType; #endif // concept requirements __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>) __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept< _RandomAccessIterator>) __glibcxx_function_requires(_ConvertibleConcept<_InputValueType, _OutputValueType>) __glibcxx_function_requires(_BinaryPredicateConcept<_Compare, _InputValueType, _OutputValueType>) __glibcxx_function_requires(_BinaryPredicateConcept<_Compare, _OutputValueType, _OutputValueType>) __glibcxx_requires_valid_range(__first, __last); __glibcxx_requires_irreflexive_pred(__first, __last, __comp); __glibcxx_requires_valid_range(__result_first, __result_last); return std::__partial_sort_copy(__first, __last, __result_first, __result_last, __gnu_cxx::__ops::__iter_comp_iter(__comp)); } /// This is a helper function for the sort routine. template<typename _RandomAccessIterator, typename _Compare> void __unguarded_linear_insert(_RandomAccessIterator __last, _Compare __comp) { typename iterator_traits<_RandomAccessIterator>::value_type __val = _GLIBCXX_MOVE(__last); _RandomAccessIterator __next = __last; --__next; while (__comp(__val, __next)) { __last = _GLIBCXX_MOVE(__next); __last = __next; --__next; } __last = _GLIBCXX_MOVE(__val); } /// This is a helper function for the sort routine. template<typename _RandomAccessIterator, typename _Compare> void __insertion_sort(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp) { if (__first == __last) return; for (_RandomAccessIterator __i = __first + 1; __i != __last; ++__i) { if (__comp(__i, __first)) { typename iterator_traits<_RandomAccessIterator>::value_type __val = _GLIBCXX_MOVE(__i); _GLIBCXX_MOVE_BACKWARD3(__first, __i, __i + 1); __first = _GLIBCXX_MOVE(__val); } else std::__unguarded_linear_insert(__i, __gnu_cxx::__ops::__val_comp_iter(__comp)); } } /// This is a helper function for the sort routine. template<typename _RandomAccessIterator, typename _Compare> inline void __unguarded_insertion_sort(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp) { for (_RandomAccessIterator __i = __first; __i != __last; ++__i) std::__unguarded_linear_insert(__i, __gnu_cxx::__ops::__val_comp_iter(__comp)); } /* * @doctodo * This controls some aspect of the sort routines. / enum { _S_threshold = 16 }; /// This is a helper function for the sort routine. template<typename _RandomAccessIterator, typename _Compare> void __final_insertion_sort(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp) { if (__last - __first > int(_S_threshold)) { std::__insertion_sort(__first, __first + int(_S_threshold), __comp); std::__unguarded_insertion_sort(__first + int(_S_threshold), __last, __comp); } else std::__insertion_sort(__first, __last, __comp); } /// This is a helper function... template<typename _RandomAccessIterator, typename _Compare> _RandomAccessIterator __unguarded_partition(_RandomAccessIterator __first, _RandomAccessIterator __last, _RandomAccessIterator __pivot, _Compare __comp) { while (true) { while (__comp(__first, __pivot)) ++__first; --__last; while (__comp(__pivot, __last)) --__last; if (!(__first < __last)) return __first; std::iter_swap(__first, __last); ++__first; } } /// This is a helper function... template<typename _RandomAccessIterator, typename _Compare> inline _RandomAccessIterator __unguarded_partition_pivot(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp) { _RandomAccessIterator __mid = __first + (__last - __first) / 2; std::__move_median_to_first(__first, __first + 1, __mid, __last - 1, __comp); return std::__unguarded_partition(__first + 1, __last, __first, __comp); } template<typename _RandomAccessIterator, typename _Compare> inline void __partial_sort(_RandomAccessIterator __first, _RandomAccessIterator __middle, _RandomAccessIterator __last, _Compare __comp) { std::__heap_select(__first, __middle, __last, __comp); std::__sort_heap(__first, __middle, __comp); } /// This is a helper function for the sort routine. template<typename _RandomAccessIterator, typename _Size, typename _Compare> void __introsort_loop(_RandomAccessIterator __first, _RandomAccessIterator __last, _Size __depth_limit, _Compare __comp) { while (__last - __first > int(_S_threshold)) { if (__depth_limit == 0) { std::__partial_sort(__first, __last, __last, __comp); return; } --__depth_limit; _RandomAccessIterator __cut = std::__unguarded_partition_pivot(__first, __last, __comp); std::__introsort_loop(__cut, __last, __depth_limit, __comp); __last = __cut; } } // sort template<typename _RandomAccessIterator, typename _Compare> inline void __sort(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp) { if (__first != __last) { std::__introsort_loop(__first, __last, std::__lg(__last - __first) 2, __comp); std::__final_insertion_sort(__first, __last, __comp); } } template<typename _RandomAccessIterator, typename _Size, typename _Compare> void __introselect(_RandomAccessIterator __first, _RandomAccessIterator __nth, _RandomAccessIterator __last, _Size __depth_limit, _Compare __comp) { while (__last - __first > 3) { if (__depth_limit == 0) { std::__heap_select(__first, __nth + 1, __last, __comp); // Place the nth largest element in its final position. std::iter_swap(__first, __nth); return; } --__depth_limit; _RandomAccessIterator __cut = std::__unguarded_partition_pivot(__first, __last, __comp); if (__cut <= __nth) __first = __cut; else __last = __cut; } std::__insertion_sort(__first, __last, __comp); } // nth_element // lower_bound moved to stl_algobase.h /** * @brief Finds the first position in which @p __val could be inserted * without changing the ordering. * @ingroup binary_search_algorithms * @param __first An iterator. * @param __last Another iterator. * @param __val The search term. * @param __comp A functor to use for comparisons. * @return An iterator pointing to the first element <em>not less * than</em> @p __val, or end() if every element is less * than @p __val. * @ingroup binary_search_algorithms * * The comparison function should have the same effects on ordering as * the function used for the initial sort. / template<typename _ForwardIterator, typename _Tp, typename _Compare> inline _ForwardIterator lower_bound(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __val, _Compare __comp) { // concept requirements __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>) __glibcxx_function_requires(_BinaryPredicateConcept<_Compare, typename iterator_traits<_ForwardIterator>::value_type, _Tp>) __glibcxx_requires_partitioned_lower_pred(__first, __last, __val, __comp); return std::__lower_bound(__first, __last, __val, __gnu_cxx::__ops::__iter_comp_val(__comp)); } template<typename _ForwardIterator, typename _Tp, typename _Compare> _ForwardIterator __upper_bound(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __val, _Compare __comp) { typedef typename iterator_traits<_ForwardIterator>::difference_type _DistanceType; _DistanceType __len = std::distance(__first, __last); while (__len > 0) { _DistanceType __half = __len >> 1; _ForwardIterator __middle = __first; std::advance(__middle, __half); if (__comp(__val, __middle)) __len = __half; else { __first = __middle; ++__first; __len = __len - __half - 1; } } return __first; } /* * @brief Finds the last position in which @p __val could be inserted * without changing the ordering. * @ingroup binary_search_algorithms * @param __first An iterator. * @param __last Another iterator. * @param __val The search term. * @return An iterator pointing to the first element greater than @p __val, * or end() if no elements are greater than @p __val. * @ingroup binary_search_algorithms / template<typename _ForwardIterator, typename _Tp> inline _ForwardIterator upper_bound(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __val) { // concept requirements __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>) __glibcxx_function_requires(_LessThanOpConcept< _Tp, typename iterator_traits<_ForwardIterator>::value_type>) __glibcxx_requires_partitioned_upper(__first, __last, __val); return std::__upper_bound(__first, __last, __val, __gnu_cxx::__ops::__val_less_iter()); } /* * @brief Finds the last position in which @p __val could be inserted * without changing the ordering. * @ingroup binary_search_algorithms * @param __first An iterator. * @param __last Another iterator. * @param __val The search term. * @param __comp A functor to use for comparisons. * @return An iterator pointing to the first element greater than @p __val, * or end() if no elements are greater than @p __val. * @ingroup binary_search_algorithms * * The comparison function should have the same effects on ordering as * the function used for the initial sort. / template<typename _ForwardIterator, typename _Tp, typename _Compare> inline _ForwardIterator upper_bound(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __val, _Compare __comp) { // concept requirements __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>) __glibcxx_function_requires(_BinaryPredicateConcept<_Compare, _Tp, typename iterator_traits<_ForwardIterator>::value_type>) __glibcxx_requires_partitioned_upper_pred(__first, __last, __val, __comp); return std::__upper_bound(__first, __last, __val, __gnu_cxx::__ops::__val_comp_iter(__comp)); } template<typename _ForwardIterator, typename _Tp, typename _CompareItTp, typename _CompareTpIt> pair<_ForwardIterator, _ForwardIterator> __equal_range(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __val, _CompareItTp __comp_it_val, _CompareTpIt __comp_val_it) { typedef typename iterator_traits<_ForwardIterator>::difference_type _DistanceType; _DistanceType __len = std::distance(__first, __last); while (__len > 0) { _DistanceType __half = __len >> 1; _ForwardIterator __middle = __first; std::advance(__middle, __half); if (__comp_it_val(__middle, __val)) { __first = __middle; ++__first; __len = __len - __half - 1; } else if (__comp_val_it(__val, __middle)) __len = __half; else { _ForwardIterator __left = std::__lower_bound(__first, __middle, __val, __comp_it_val); std::advance(__first, __len); _ForwardIterator __right = std::__upper_bound(++__middle, __first, __val, __comp_val_it); return pair<_ForwardIterator, _ForwardIterator>(__left, __right); } } return pair<_ForwardIterator, _ForwardIterator>(__first, __first); } /* * @brief Finds the largest subrange in which @p __val could be inserted * at any place in it without changing the ordering. * @ingroup binary_search_algorithms * @param __first An iterator. * @param __last Another iterator. * @param __val The search term. * @return An pair of iterators defining the subrange. * @ingroup binary_search_algorithms * * This is equivalent to * @code * std::make_pair(lower_bound(__first, __last, __val), * upper_bound(__first, __last, __val)) * @endcode * but does not actually call those functions. / template<typename _ForwardIterator, typename _Tp> inline pair<_ForwardIterator, _ForwardIterator> equal_range(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __val) { // concept requirements __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>) __glibcxx_function_requires(_LessThanOpConcept< typename iterator_traits<_ForwardIterator>::value_type, _Tp>) __glibcxx_function_requires(_LessThanOpConcept< _Tp, typename iterator_traits<_ForwardIterator>::value_type>) __glibcxx_requires_partitioned_lower(__first, __last, __val); __glibcxx_requires_partitioned_upper(__first, __last, __val); return std::__equal_range(__first, __last, __val, __gnu_cxx::__ops::__iter_less_val(), __gnu_cxx::__ops::__val_less_iter()); } /* * @brief Finds the largest subrange in which @p __val could be inserted * at any place in it without changing the ordering. * @param __first An iterator. * @param __last Another iterator. * @param __val The search term. * @param __comp A functor to use for comparisons. * @return An pair of iterators defining the subrange. * @ingroup binary_search_algorithms * * This is equivalent to * @code * std::make_pair(lower_bound(__first, __last, __val, __comp), * upper_bound(__first, __last, __val, __comp)) * @endcode * but does not actually call those functions. / template<typename _ForwardIterator, typename _Tp, typename _Compare> inline pair<_ForwardIterator, _ForwardIterator> equal_range(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __val, _Compare __comp) { // concept requirements __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>) __glibcxx_function_requires(_BinaryPredicateConcept<_Compare, typename iterator_traits<_ForwardIterator>::value_type, _Tp>) __glibcxx_function_requires(_BinaryPredicateConcept<_Compare, _Tp, typename iterator_traits<_ForwardIterator>::value_type>) __glibcxx_requires_partitioned_lower_pred(__first, __last, __val, __comp); __glibcxx_requires_partitioned_upper_pred(__first, __last, __val, __comp); return std::__equal_range(__first, __last, __val, __gnu_cxx::__ops::__iter_comp_val(__comp), __gnu_cxx::__ops::__val_comp_iter(__comp)); } /* * @brief Determines whether an element exists in a range. * @ingroup binary_search_algorithms * @param __first An iterator. * @param __last Another iterator. * @param __val The search term. * @return True if @p __val (or its equivalent) is in [@p * __first,@p __last ]. * * Note that this does not actually return an iterator to @p __val. For * that, use std::find or a container's specialized find member functions. / template<typename _ForwardIterator, typename _Tp> bool binary_search(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __val) { // concept requirements __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>) __glibcxx_function_requires(_LessThanOpConcept< _Tp, typename iterator_traits<_ForwardIterator>::value_type>) __glibcxx_requires_partitioned_lower(__first, __last, __val); __glibcxx_requires_partitioned_upper(__first, __last, __val); _ForwardIterator __i = std::__lower_bound(__first, __last, __val, __gnu_cxx::__ops::__iter_less_val()); return __i != __last && !(__val < __i); } /** * @brief Determines whether an element exists in a range. * @ingroup binary_search_algorithms * @param __first An iterator. * @param __last Another iterator. * @param __val The search term. * @param __comp A functor to use for comparisons. * @return True if @p __val (or its equivalent) is in @p [__first,__last]. * * Note that this does not actually return an iterator to @p __val. For * that, use std::find or a container's specialized find member functions. * * The comparison function should have the same effects on ordering as * the function used for the initial sort. / template<typename _ForwardIterator, typename _Tp, typename _Compare> bool binary_search(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __val, _Compare __comp) { // concept requirements __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>) __glibcxx_function_requires(_BinaryPredicateConcept<_Compare, _Tp, typename iterator_traits<_ForwardIterator>::value_type>) __glibcxx_requires_partitioned_lower_pred(__first, __last, __val, __comp); __glibcxx_requires_partitioned_upper_pred(__first, __last, __val, __comp); _ForwardIterator __i = std::__lower_bound(__first, __last, __val, __gnu_cxx::__ops::__iter_comp_val(__comp)); return __i != __last && !bool(__comp(__val, __i)); } // merge /// This is a helper function for the __merge_adaptive routines. template<typename _InputIterator1, typename _InputIterator2, typename _OutputIterator, typename _Compare> void __move_merge_adaptive(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp) { while (__first1 != __last1 && __first2 != __last2) { if (__comp(__first2, __first1)) { __result = _GLIBCXX_MOVE(__first2); ++__first2; } else { __result = _GLIBCXX_MOVE(__first1); ++__first1; } ++__result; } if (__first1 != __last1) _GLIBCXX_MOVE3(__first1, __last1, __result); } /// This is a helper function for the __merge_adaptive routines. template<typename _BidirectionalIterator1, typename _BidirectionalIterator2, typename _BidirectionalIterator3, typename _Compare> void __move_merge_adaptive_backward(_BidirectionalIterator1 __first1, _BidirectionalIterator1 __last1, _BidirectionalIterator2 __first2, _BidirectionalIterator2 __last2, _BidirectionalIterator3 __result, _Compare __comp) { if (__first1 == __last1) { _GLIBCXX_MOVE_BACKWARD3(__first2, __last2, __result); return; } else if (__first2 == __last2) return; --__last1; --__last2; while (true) { if (__comp(__last2, __last1)) { --__result = _GLIBCXX_MOVE(__last1); if (__first1 == __last1) { _GLIBCXX_MOVE_BACKWARD3(__first2, ++__last2, __result); return; } --__last1; } else { --__result = _GLIBCXX_MOVE(__last2); if (__first2 == __last2) return; --__last2; } } } /// This is a helper function for the merge routines. template<typename _BidirectionalIterator1, typename _BidirectionalIterator2, typename _Distance> _BidirectionalIterator1 __rotate_adaptive(_BidirectionalIterator1 __first, _BidirectionalIterator1 __middle, _BidirectionalIterator1 __last, _Distance __len1, _Distance __len2, _BidirectionalIterator2 __buffer, _Distance __buffer_size) { _BidirectionalIterator2 __buffer_end; if (__len1 > __len2 && __len2 <= __buffer_size) { if (__len2) { __buffer_end = _GLIBCXX_MOVE3(__middle, __last, __buffer); _GLIBCXX_MOVE_BACKWARD3(__first, __middle, __last); return _GLIBCXX_MOVE3(__buffer, __buffer_end, __first); } else return __first; } else if (__len1 <= __buffer_size) { if (__len1) { __buffer_end = _GLIBCXX_MOVE3(__first, __middle, __buffer); _GLIBCXX_MOVE3(__middle, __last, __first); return _GLIBCXX_MOVE_BACKWARD3(__buffer, __buffer_end, __last); } else return __last; } else { std::rotate(__first, __middle, __last); std::advance(__first, std::distance(__middle, __last)); return __first; } } /// This is a helper function for the merge routines. template<typename _BidirectionalIterator, typename _Distance, typename _Pointer, typename _Compare> void __merge_adaptive(_BidirectionalIterator __first, _BidirectionalIterator __middle, _BidirectionalIterator __last, _Distance __len1, _Distance __len2, _Pointer __buffer, _Distance __buffer_size, _Compare __comp) { if (__len1 <= __len2 && __len1 <= __buffer_size) { _Pointer __buffer_end = _GLIBCXX_MOVE3(__first, __middle, __buffer); std::__move_merge_adaptive(__buffer, __buffer_end, __middle, __last, __first, __comp); } else if (__len2 <= __buffer_size) { _Pointer __buffer_end = _GLIBCXX_MOVE3(__middle, __last, __buffer); std::__move_merge_adaptive_backward(__first, __middle, __buffer, __buffer_end, __last, __comp); } else { _BidirectionalIterator __first_cut = __first; _BidirectionalIterator __second_cut = __middle; _Distance __len11 = 0; _Distance __len22 = 0; if (__len1 > __len2) { __len11 = __len1 / 2; std::advance(__first_cut, __len11); __second_cut = std::__lower_bound(__middle, __last, __first_cut, __gnu_cxx::__ops::__iter_comp_val(__comp)); __len22 = std::distance(__middle, __second_cut); } else { __len22 = __len2 / 2; std::advance(__second_cut, __len22); __first_cut = std::__upper_bound(__first, __middle, __second_cut, __gnu_cxx::__ops::__val_comp_iter(__comp)); __len11 = std::distance(__first, __first_cut); } _BidirectionalIterator __new_middle = std::__rotate_adaptive(__first_cut, __middle, __second_cut, __len1 - __len11, __len22, __buffer, __buffer_size); std::__merge_adaptive(__first, __first_cut, __new_middle, __len11, __len22, __buffer, __buffer_size, __comp); std::__merge_adaptive(__new_middle, __second_cut, __last, __len1 - __len11, __len2 - __len22, __buffer, __buffer_size, __comp); } } /// This is a helper function for the merge routines. template<typename _BidirectionalIterator, typename _Distance, typename _Compare> void __merge_without_buffer(_BidirectionalIterator __first, _BidirectionalIterator __middle, _BidirectionalIterator __last, _Distance __len1, _Distance __len2, _Compare __comp) { if (__len1 == 0 \|\| __len2 == 0) return; if (__len1 + __len2 == 2) { if (__comp(__middle, __first)) std::iter_swap(__first, __middle); return; } _BidirectionalIterator __first_cut = __first; _BidirectionalIterator __second_cut = __middle; _Distance __len11 = 0; _Distance __len22 = 0; if (__len1 > __len2) { __len11 = __len1 / 2; std::advance(__first_cut, __len11); __second_cut = std::__lower_bound(__middle, __last, __first_cut, __gnu_cxx::__ops::__iter_comp_val(__comp)); __len22 = std::distance(__middle, __second_cut); } else { __len22 = __len2 / 2; std::advance(__second_cut, __len22); __first_cut = std::__upper_bound(__first, __middle, __second_cut, __gnu_cxx::__ops::__val_comp_iter(__comp)); __len11 = std::distance(__first, __first_cut); } std::rotate(__first_cut, __middle, __second_cut); _BidirectionalIterator __new_middle = __first_cut; std::advance(__new_middle, std::distance(__middle, __second_cut)); std::__merge_without_buffer(__first, __first_cut, __new_middle, __len11, __len22, __comp); std::__merge_without_buffer(__new_middle, __second_cut, __last, __len1 - __len11, __len2 - __len22, __comp); } template<typename _BidirectionalIterator, typename _Compare> void __inplace_merge(_BidirectionalIterator __first, _BidirectionalIterator __middle, _BidirectionalIterator __last, _Compare __comp) { typedef typename iterator_traits<_BidirectionalIterator>::value_type _ValueType; typedef typename iterator_traits<_BidirectionalIterator>::difference_type _DistanceType; if (__first == __middle \|\| __middle == __last) return; const _DistanceType __len1 = std::distance(__first, __middle); const _DistanceType __len2 = std::distance(__middle, __last); typedef _Temporary_buffer<_BidirectionalIterator, _ValueType> _TmpBuf; _TmpBuf __buf(__first, __last); if (__buf.begin() == 0) std::__merge_without_buffer (__first, __middle, __last, __len1, __len2, __comp); else std::__merge_adaptive (__first, __middle, __last, __len1, __len2, __buf.begin(), _DistanceType(__buf.size()), __comp); } /** * @brief Merges two sorted ranges in place. * @ingroup sorting_algorithms * @param __first An iterator. * @param __middle Another iterator. * @param __last Another iterator. * @return Nothing. * * Merges two sorted and consecutive ranges, [__first,__middle) and * [__middle,__last), and puts the result in [__first,__last). The * output will be sorted. The sort is @e stable, that is, for * equivalent elements in the two ranges, elements from the first * range will always come before elements from the second. * * If enough additional memory is available, this takes (__last-__first)-1 * comparisons. Otherwise an NlogN algorithm is used, where N is * distance(__first,__last). / template<typename _BidirectionalIterator> inline void inplace_merge(_BidirectionalIterator __first, _BidirectionalIterator __middle, _BidirectionalIterator __last) { // concept requirements __glibcxx_function_requires(_Mutable_BidirectionalIteratorConcept< _BidirectionalIterator>) __glibcxx_function_requires(_LessThanComparableConcept< typename iterator_traits<_BidirectionalIterator>::value_type>) __glibcxx_requires_sorted(__first, __middle); __glibcxx_requires_sorted(__middle, __last); __glibcxx_requires_irreflexive(__first, __last); std::__inplace_merge(__first, __middle, __last, __gnu_cxx::__ops::__iter_less_iter()); } /* * @brief Merges two sorted ranges in place. * @ingroup sorting_algorithms * @param __first An iterator. * @param __middle Another iterator. * @param __last Another iterator. * @param __comp A functor to use for comparisons. * @return Nothing. * * Merges two sorted and consecutive ranges, [__first,__middle) and * [middle,last), and puts the result in [__first,__last). The output will * be sorted. The sort is @e stable, that is, for equivalent * elements in the two ranges, elements from the first range will always * come before elements from the second. * * If enough additional memory is available, this takes (__last-__first)-1 * comparisons. Otherwise an NlogN algorithm is used, where N is * distance(__first,__last). * * The comparison function should have the same effects on ordering as * the function used for the initial sort. / template<typename _BidirectionalIterator, typename _Compare> inline void inplace_merge(_BidirectionalIterator __first, _BidirectionalIterator __middle, _BidirectionalIterator __last, _Compare __comp) { // concept requirements __glibcxx_function_requires(_Mutable_BidirectionalIteratorConcept< _BidirectionalIterator>) __glibcxx_function_requires(_BinaryPredicateConcept<_Compare, typename iterator_traits<_BidirectionalIterator>::value_type, typename iterator_traits<_BidirectionalIterator>::value_type>) __glibcxx_requires_sorted_pred(__first, __middle, __comp); __glibcxx_requires_sorted_pred(__middle, __last, __comp); __glibcxx_requires_irreflexive_pred(__first, __last, __comp); std::__inplace_merge(__first, __middle, __last, __gnu_cxx::__ops::__iter_comp_iter(__comp)); } /// This is a helper function for the __merge_sort_loop routines. template<typename _InputIterator, typename _OutputIterator, typename _Compare> _OutputIterator __move_merge(_InputIterator __first1, _InputIterator __last1, _InputIterator __first2, _InputIterator __last2, _OutputIterator __result, _Compare __comp) { while (__first1 != __last1 && __first2 != __last2) { if (__comp(__first2, __first1)) { __result = _GLIBCXX_MOVE(__first2); ++__first2; } else { __result = _GLIBCXX_MOVE(__first1); ++__first1; } ++__result; } return _GLIBCXX_MOVE3(__first2, __last2, _GLIBCXX_MOVE3(__first1, __last1, __result)); } template<typename _RandomAccessIterator1, typename _RandomAccessIterator2, typename _Distance, typename _Compare> void __merge_sort_loop(_RandomAccessIterator1 __first, _RandomAccessIterator1 __last, _RandomAccessIterator2 __result, _Distance __step_size, _Compare __comp) { const _Distance __two_step = 2 __step_size; while (__last - __first >= __two_step) { __result = std::__move_merge(__first, __first + __step_size, __first + __step_size, __first + __two_step, __result, __comp); __first += __two_step; } __step_size = std::min(_Distance(__last - __first), __step_size); std::__move_merge(__first, __first + __step_size, __first + __step_size, __last, __result, __comp); } template<typename _RandomAccessIterator, typename _Distance, typename _Compare> void __chunk_insertion_sort(_RandomAccessIterator __first, _RandomAccessIterator __last, _Distance __chunk_size, _Compare __comp) { while (__last - __first >= __chunk_size) { std::__insertion_sort(__first, __first + __chunk_size, __comp); __first += __chunk_size; } std::__insertion_sort(__first, __last, __comp); } enum { _S_chunk_size = 7 }; template<typename _RandomAccessIterator, typename _Pointer, typename _Compare> void __merge_sort_with_buffer(_RandomAccessIterator __first, _RandomAccessIterator __last, _Pointer __buffer, _Compare __comp) { typedef typename iterator_traits<_RandomAccessIterator>::difference_type _Distance; const _Distance __len = __last - __first; const _Pointer __buffer_last = __buffer + __len; _Distance __step_size = _S_chunk_size; std::__chunk_insertion_sort(__first, __last, __step_size, __comp); while (__step_size < __len) { std::__merge_sort_loop(__first, __last, __buffer, __step_size, __comp); __step_size = 2; std::__merge_sort_loop(__buffer, __buffer_last, __first, __step_size, __comp); __step_size = 2; } } template<typename _RandomAccessIterator, typename _Pointer, typename _Distance, typename _Compare> void __stable_sort_adaptive(_RandomAccessIterator __first, _RandomAccessIterator __last, _Pointer __buffer, _Distance __buffer_size, _Compare __comp) { const _Distance __len = (__last - __first + 1) / 2; const _RandomAccessIterator __middle = __first + __len; if (__len > __buffer_size) { std::__stable_sort_adaptive(__first, __middle, __buffer, __buffer_size, __comp); std::__stable_sort_adaptive(__middle, __last, __buffer, __buffer_size, __comp); } else { std::__merge_sort_with_buffer(__first, __middle, __buffer, __comp); std::__merge_sort_with_buffer(__middle, __last, __buffer, __comp); } std::__merge_adaptive(__first, __middle, __last, _Distance(__middle - __first), _Distance(__last - __middle), __buffer, __buffer_size, __comp); } /// This is a helper function for the stable sorting routines. template<typename _RandomAccessIterator, typename _Compare> void __inplace_stable_sort(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp) { if (__last - __first < 15) { std::__insertion_sort(__first, __last, __comp); return; } _RandomAccessIterator __middle = __first + (__last - __first) / 2; std::__inplace_stable_sort(__first, __middle, __comp); std::__inplace_stable_sort(__middle, __last, __comp); std::__merge_without_buffer(__first, __middle, __last, __middle - __first, __last - __middle, __comp); } // stable_sort // Set algorithms: includes, set_union, set_intersection, set_difference, // set_symmetric_difference. All of these algorithms have the precondition // that their input ranges are sorted and the postcondition that their output // ranges are sorted. template<typename _InputIterator1, typename _InputIterator2, typename _Compare> bool __includes(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _InputIterator2 __last2, _Compare __comp) { while (__first1 != __last1 && __first2 != __last2) if (__comp(__first2, __first1)) return false; else if (__comp(__first1, __first2)) ++__first1; else { ++__first1; ++__first2; } return __first2 == __last2; } /** * @brief Determines whether all elements of a sequence exists in a range. * @param __first1 Start of search range. * @param __last1 End of search range. * @param __first2 Start of sequence * @param __last2 End of sequence. * @return True if each element in [__first2,__last2) is contained in order * within [__first1,__last1). False otherwise. * @ingroup set_algorithms * * This operation expects both [__first1,__last1) and * [__first2,__last2) to be sorted. Searches for the presence of * each element in [__first2,__last2) within [__first1,__last1). * The iterators over each range only move forward, so this is a * linear algorithm. If an element in [__first2,__last2) is not * found before the search iterator reaches @p __last2, false is * returned. / template<typename _InputIterator1, typename _InputIterator2> inline bool includes(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _InputIterator2 __last2) { // concept requirements __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>) __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>) __glibcxx_function_requires(_LessThanOpConcept< typename iterator_traits<_InputIterator1>::value_type, typename iterator_traits<_InputIterator2>::value_type>) __glibcxx_function_requires(_LessThanOpConcept< typename iterator_traits<_InputIterator2>::value_type, typename iterator_traits<_InputIterator1>::value_type>) __glibcxx_requires_sorted_set(__first1, __last1, __first2); __glibcxx_requires_sorted_set(__first2, __last2, __first1); __glibcxx_requires_irreflexive2(__first1, __last1); __glibcxx_requires_irreflexive2(__first2, __last2); return std::__includes(__first1, __last1, __first2, __last2, __gnu_cxx::__ops::__iter_less_iter()); } /* * @brief Determines whether all elements of a sequence exists in a range * using comparison. * @ingroup set_algorithms * @param __first1 Start of search range. * @param __last1 End of search range. * @param __first2 Start of sequence * @param __last2 End of sequence. * @param __comp Comparison function to use. * @return True if each element in [__first2,__last2) is contained * in order within [__first1,__last1) according to comp. False * otherwise. @ingroup set_algorithms * * This operation expects both [__first1,__last1) and * [__first2,__last2) to be sorted. Searches for the presence of * each element in [__first2,__last2) within [__first1,__last1), * using comp to decide. The iterators over each range only move * forward, so this is a linear algorithm. If an element in * [__first2,__last2) is not found before the search iterator * reaches @p __last2, false is returned. / template<typename _InputIterator1, typename _InputIterator2, typename _Compare> inline bool includes(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _InputIterator2 __last2, _Compare __comp) { // concept requirements __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>) __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>) __glibcxx_function_requires(_BinaryPredicateConcept<_Compare, typename iterator_traits<_InputIterator1>::value_type, typename iterator_traits<_InputIterator2>::value_type>) __glibcxx_function_requires(_BinaryPredicateConcept<_Compare, typename iterator_traits<_InputIterator2>::value_type, typename iterator_traits<_InputIterator1>::value_type>) __glibcxx_requires_sorted_set_pred(__first1, __last1, __first2, __comp); __glibcxx_requires_sorted_set_pred(__first2, __last2, __first1, __comp); __glibcxx_requires_irreflexive_pred2(__first1, __last1, __comp); __glibcxx_requires_irreflexive_pred2(__first2, __last2, __comp); return std::__includes(__first1, __last1, __first2, __last2, __gnu_cxx::__ops::__iter_comp_iter(__comp)); } // nth_element // merge // set_difference // set_intersection // set_union // stable_sort // set_symmetric_difference // min_element // max_element template<typename _BidirectionalIterator, typename _Compare> bool __next_permutation(_BidirectionalIterator __first, _BidirectionalIterator __last, _Compare __comp) { if (__first == __last) return false; _BidirectionalIterator __i = __first; ++__i; if (__i == __last) return false; __i = __last; --__i; for(;;) { _BidirectionalIterator __ii = __i; --__i; if (__comp(__i, __ii)) { _BidirectionalIterator __j = __last; while (!__comp(__i, --__j)) {} std::iter_swap(__i, __j); std::__reverse(__ii, __last, std::__iterator_category(__first)); return true; } if (__i == __first) { std::__reverse(__first, __last, std::__iterator_category(__first)); return false; } } } /* * @brief Permute range into the next @e dictionary ordering. * @ingroup sorting_algorithms * @param __first Start of range. * @param __last End of range. * @return False if wrapped to first permutation, true otherwise. * * Treats all permutations of the range as a set of @e dictionary sorted * sequences. Permutes the current sequence into the next one of this set. * Returns true if there are more sequences to generate. If the sequence * is the largest of the set, the smallest is generated and false returned. / template<typename _BidirectionalIterator> inline bool next_permutation(_BidirectionalIterator __first, _BidirectionalIterator __last) { // concept requirements __glibcxx_function_requires(_BidirectionalIteratorConcept< _BidirectionalIterator>) __glibcxx_function_requires(_LessThanComparableConcept< typename iterator_traits<_BidirectionalIterator>::value_type>) __glibcxx_requires_valid_range(__first, __last); __glibcxx_requires_irreflexive(__first, __last); return std::__next_permutation (__first, __last, __gnu_cxx::__ops::__iter_less_iter()); } /* * @brief Permute range into the next @e dictionary ordering using * comparison functor. * @ingroup sorting_algorithms * @param __first Start of range. * @param __last End of range. * @param __comp A comparison functor. * @return False if wrapped to first permutation, true otherwise. * * Treats all permutations of the range [__first,__last) as a set of * @e dictionary sorted sequences ordered by @p __comp. Permutes the current * sequence into the next one of this set. Returns true if there are more * sequences to generate. If the sequence is the largest of the set, the * smallest is generated and false returned. / template<typename _BidirectionalIterator, typename _Compare> inline bool next_permutation(_BidirectionalIterator __first, _BidirectionalIterator __last, _Compare __comp) { // concept requirements __glibcxx_function_requires(_BidirectionalIteratorConcept< _BidirectionalIterator>) __glibcxx_function_requires(_BinaryPredicateConcept<_Compare, typename iterator_traits<_BidirectionalIterator>::value_type, typename iterator_traits<_BidirectionalIterator>::value_type>) __glibcxx_requires_valid_range(__first, __last); __glibcxx_requires_irreflexive_pred(__first, __last, __comp); return std::__next_permutation (__first, __last, __gnu_cxx::__ops::__iter_comp_iter(__comp)); } template<typename _BidirectionalIterator, typename _Compare> bool __prev_permutation(_BidirectionalIterator __first, _BidirectionalIterator __last, _Compare __comp) { if (__first == __last) return false; _BidirectionalIterator __i = __first; ++__i; if (__i == __last) return false; __i = __last; --__i; for(;;) { _BidirectionalIterator __ii = __i; --__i; if (__comp(__ii, __i)) { _BidirectionalIterator __j = __last; while (!__comp(--__j, __i)) {} std::iter_swap(__i, __j); std::__reverse(__ii, __last, std::__iterator_category(__first)); return true; } if (__i == __first) { std::__reverse(__first, __last, std::__iterator_category(__first)); return false; } } } /* * @brief Permute range into the previous @e dictionary ordering. * @ingroup sorting_algorithms * @param __first Start of range. * @param __last End of range. * @return False if wrapped to last permutation, true otherwise. * * Treats all permutations of the range as a set of @e dictionary sorted * sequences. Permutes the current sequence into the previous one of this * set. Returns true if there are more sequences to generate. If the * sequence is the smallest of the set, the largest is generated and false * returned. / template<typename _BidirectionalIterator> inline bool prev_permutation(_BidirectionalIterator __first, _BidirectionalIterator __last) { // concept requirements __glibcxx_function_requires(_BidirectionalIteratorConcept< _BidirectionalIterator>) __glibcxx_function_requires(_LessThanComparableConcept< typename iterator_traits<_BidirectionalIterator>::value_type>) __glibcxx_requires_valid_range(__first, __last); __glibcxx_requires_irreflexive(__first, __last); return std::__prev_permutation(__first, __last, __gnu_cxx::__ops::__iter_less_iter()); } /* * @brief Permute range into the previous @e dictionary ordering using * comparison functor. * @ingroup sorting_algorithms * @param __first Start of range. * @param __last End of range. * @param __comp A comparison functor. * @return False if wrapped to last permutation, true otherwise. * * Treats all permutations of the range [__first,__last) as a set of * @e dictionary sorted sequences ordered by @p __comp. Permutes the current * sequence into the previous one of this set. Returns true if there are * more sequences to generate. If the sequence is the smallest of the set, * the largest is generated and false returned. / template<typename _BidirectionalIterator, typename _Compare> inline bool prev_permutation(_BidirectionalIterator __first, _BidirectionalIterator __last, _Compare __comp) { // concept requirements __glibcxx_function_requires(_BidirectionalIteratorConcept< _BidirectionalIterator>) __glibcxx_function_requires(_BinaryPredicateConcept<_Compare, typename iterator_traits<_BidirectionalIterator>::value_type, typename iterator_traits<_BidirectionalIterator>::value_type>) __glibcxx_requires_valid_range(__first, __last); __glibcxx_requires_irreflexive_pred(__first, __last, __comp); return std::__prev_permutation(__first, __last, __gnu_cxx::__ops::__iter_comp_iter(__comp)); } // replace // replace_if template<typename _InputIterator, typename _OutputIterator, typename _Predicate, typename _Tp> _OutputIterator __replace_copy_if(_InputIterator __first, _InputIterator __last, _OutputIterator __result, _Predicate __pred, const _Tp& __new_value) { for (; __first != __last; ++__first, (void)++__result) if (__pred(__first)) __result = __new_value; else __result = __first; return __result; } /** * @brief Copy a sequence, replacing each element of one value with another * value. * @param __first An input iterator. * @param __last An input iterator. * @param __result An output iterator. * @param __old_value The value to be replaced. * @param __new_value The replacement value. * @return The end of the output sequence, @p result+(last-first). * * Copies each element in the input range @p [__first,__last) to the * output range @p [__result,__result+(__last-__first)) replacing elements * equal to @p __old_value with @p __new_value. / template<typename _InputIterator, typename _OutputIterator, typename _Tp> inline _OutputIterator replace_copy(_InputIterator __first, _InputIterator __last, _OutputIterator __result, const _Tp& __old_value, const _Tp& __new_value) { // concept requirements __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>) __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator, typename iterator_traits<_InputIterator>::value_type>) __glibcxx_function_requires(_EqualOpConcept< typename iterator_traits<_InputIterator>::value_type, _Tp>) __glibcxx_requires_valid_range(__first, __last); return std::__replace_copy_if(__first, __last, __result, __gnu_cxx::__ops::__iter_equals_val(__old_value), __new_value); } /* * @brief Copy a sequence, replacing each value for which a predicate * returns true with another value. * @ingroup mutating_algorithms * @param __first An input iterator. * @param __last An input iterator. * @param __result An output iterator. * @param __pred A predicate. * @param __new_value The replacement value. * @return The end of the output sequence, @p __result+(__last-__first). * * Copies each element in the range @p [__first,__last) to the range * @p [__result,__result+(__last-__first)) replacing elements for which * @p __pred returns true with @p __new_value. / template<typename _InputIterator, typename _OutputIterator, typename _Predicate, typename _Tp> inline _OutputIterator replace_copy_if(_InputIterator __first, _InputIterator __last, _OutputIterator __result, _Predicate __pred, const _Tp& __new_value) { // concept requirements __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>) __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator, typename iterator_traits<_InputIterator>::value_type>) __glibcxx_function_requires(_UnaryPredicateConcept<_Predicate, typename iterator_traits<_InputIterator>::value_type>) __glibcxx_requires_valid_range(__first, __last); return std::__replace_copy_if(__first, __last, __result, __gnu_cxx::__ops::__pred_iter(__pred), __new_value); } template<typename _InputIterator, typename _Predicate> typename iterator_traits<_InputIterator>::difference_type __count_if(_InputIterator __first, _InputIterator __last, _Predicate __pred) { typename iterator_traits<_InputIterator>::difference_type __n = 0; for (; __first != __last; ++__first) if (__pred(__first)) ++__n; return __n; } #if __cplusplus >= 201103L /* * @brief Determines whether the elements of a sequence are sorted. * @ingroup sorting_algorithms * @param __first An iterator. * @param __last Another iterator. * @return True if the elements are sorted, false otherwise. / template<typename _ForwardIterator> inline bool is_sorted(_ForwardIterator __first, _ForwardIterator __last) { return std::is_sorted_until(__first, __last) == __last; } /* * @brief Determines whether the elements of a sequence are sorted * according to a comparison functor. * @ingroup sorting_algorithms * @param __first An iterator. * @param __last Another iterator. * @param __comp A comparison functor. * @return True if the elements are sorted, false otherwise. / template<typename _ForwardIterator, typename _Compare> inline bool is_sorted(_ForwardIterator __first, _ForwardIterator __last, _Compare __comp) { return std::is_sorted_until(__first, __last, __comp) == __last; } template<typename _ForwardIterator, typename _Compare> _ForwardIterator __is_sorted_until(_ForwardIterator __first, _ForwardIterator __last, _Compare __comp) { if (__first == __last) return __last; _ForwardIterator __next = __first; for (++__next; __next != __last; __first = __next, (void)++__next) if (__comp(__next, __first)) return __next; return __next; } /* * @brief Determines the end of a sorted sequence. * @ingroup sorting_algorithms * @param __first An iterator. * @param __last Another iterator. * @return An iterator pointing to the last iterator i in [__first, __last) * for which the range [__first, i) is sorted. / template<typename _ForwardIterator> inline _ForwardIterator is_sorted_until(_ForwardIterator __first, _ForwardIterator __last) { // concept requirements __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>) __glibcxx_function_requires(_LessThanComparableConcept< typename iterator_traits<_ForwardIterator>::value_type>) __glibcxx_requires_valid_range(__first, __last); __glibcxx_requires_irreflexive(__first, __last); return std::__is_sorted_until(__first, __last, __gnu_cxx::__ops::__iter_less_iter()); } /* * @brief Determines the end of a sorted sequence using comparison functor. * @ingroup sorting_algorithms * @param __first An iterator. * @param __last Another iterator. * @param __comp A comparison functor. * @return An iterator pointing to the last iterator i in [__first, __last) * for which the range [__first, i) is sorted. / template<typename _ForwardIterator, typename _Compare> inline _ForwardIterator is_sorted_until(_ForwardIterator __first, _ForwardIterator __last, _Compare __comp) { // concept requirements __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>) __glibcxx_function_requires(_BinaryPredicateConcept<_Compare, typename iterator_traits<_ForwardIterator>::value_type, typename iterator_traits<_ForwardIterator>::value_type>) __glibcxx_requires_valid_range(__first, __last); __glibcxx_requires_irreflexive_pred(__first, __last, __comp); return std::__is_sorted_until(__first, __last, __gnu_cxx::__ops::__iter_comp_iter(__comp)); } /* * @brief Determines min and max at once as an ordered pair. * @ingroup sorting_algorithms * @param __a A thing of arbitrary type. * @param __b Another thing of arbitrary type. * @return A pair(__b, __a) if __b is smaller than __a, pair(__a, * __b) otherwise. / template<typename _Tp> _GLIBCXX14_CONSTEXPR inline pair<const _Tp&, const _Tp&> minmax(const _Tp& __a, const _Tp& __b) { // concept requirements __glibcxx_function_requires(_LessThanComparableConcept<_Tp>) return __b < __a ? pair<const _Tp&, const _Tp&>(__b, __a) : pair<const _Tp&, const _Tp&>(__a, __b); } /* * @brief Determines min and max at once as an ordered pair. * @ingroup sorting_algorithms * @param __a A thing of arbitrary type. * @param __b Another thing of arbitrary type. * @param __comp A @link comparison_functors comparison functor @endlink. * @return A pair(__b, __a) if __b is smaller than __a, pair(__a, * __b) otherwise. / template<typename _Tp, typename _Compare> _GLIBCXX14_CONSTEXPR inline pair<const _Tp&, const _Tp&> minmax(const _Tp& __a, const _Tp& __b, _Compare __comp) { return __comp(__b, __a) ? pair<const _Tp&, const _Tp&>(__b, __a) : pair<const _Tp&, const _Tp&>(__a, __b); } template<typename _ForwardIterator, typename _Compare> _GLIBCXX14_CONSTEXPR pair<_ForwardIterator, _ForwardIterator> __minmax_element(_ForwardIterator __first, _ForwardIterator __last, _Compare __comp) { _ForwardIterator __next = __first; if (__first == __last \|\| ++__next == __last) return std::make_pair(__first, __first); _ForwardIterator __min{}, __max{}; if (__comp(__next, __first)) { __min = __next; __max = __first; } else { __min = __first; __max = __next; } __first = __next; ++__first; while (__first != __last) { __next = __first; if (++__next == __last) { if (__comp(__first, __min)) __min = __first; else if (!__comp(__first, __max)) __max = __first; break; } if (__comp(__next, __first)) { if (__comp(__next, __min)) __min = __next; if (!__comp(__first, __max)) __max = __first; } else { if (__comp(__first, __min)) __min = __first; if (!__comp(__next, __max)) __max = __next; } __first = __next; ++__first; } return std::make_pair(__min, __max); } /* * @brief Return a pair of iterators pointing to the minimum and maximum * elements in a range. * @ingroup sorting_algorithms * @param __first Start of range. * @param __last End of range. * @return make_pair(m, M), where m is the first iterator i in * [__first, __last) such that no other element in the range is * smaller, and where M is the last iterator i in [__first, __last) * such that no other element in the range is larger. / template<typename _ForwardIterator> _GLIBCXX14_CONSTEXPR inline pair<_ForwardIterator, _ForwardIterator> minmax_element(_ForwardIterator __first, _ForwardIterator __last) { // concept requirements __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>) __glibcxx_function_requires(_LessThanComparableConcept< typename iterator_traits<_ForwardIterator>::value_type>) __glibcxx_requires_valid_range(__first, __last); __glibcxx_requires_irreflexive(__first, __last); return std::__minmax_element(__first, __last, __gnu_cxx::__ops::__iter_less_iter()); } /* * @brief Return a pair of iterators pointing to the minimum and maximum * elements in a range. * @ingroup sorting_algorithms * @param __first Start of range. * @param __last End of range. * @param __comp Comparison functor. * @return make_pair(m, M), where m is the first iterator i in * [__first, __last) such that no other element in the range is * smaller, and where M is the last iterator i in [__first, __last) * such that no other element in the range is larger. / template<typename _ForwardIterator, typename _Compare> _GLIBCXX14_CONSTEXPR inline pair<_ForwardIterator, _ForwardIterator> minmax_element(_ForwardIterator __first, _ForwardIterator __last, _Compare __comp) { // concept requirements __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>) __glibcxx_function_requires(_BinaryPredicateConcept<_Compare, typename iterator_traits<_ForwardIterator>::value_type, typename iterator_traits<_ForwardIterator>::value_type>) __glibcxx_requires_valid_range(__first, __last); __glibcxx_requires_irreflexive_pred(__first, __last, __comp); return std::__minmax_element(__first, __last, __gnu_cxx::__ops::__iter_comp_iter(__comp)); } // N2722 + DR 915. template<typename _Tp> _GLIBCXX14_CONSTEXPR inline _Tp min(initializer_list<_Tp> __l) { return std::min_element(__l.begin(), __l.end()); } template<typename _Tp, typename _Compare> _GLIBCXX14_CONSTEXPR inline _Tp min(initializer_list<_Tp> __l, _Compare __comp) { return std::min_element(__l.begin(), __l.end(), __comp); } template<typename _Tp> _GLIBCXX14_CONSTEXPR inline _Tp max(initializer_list<_Tp> __l) { return std::max_element(__l.begin(), __l.end()); } template<typename _Tp, typename _Compare> _GLIBCXX14_CONSTEXPR inline _Tp max(initializer_list<_Tp> __l, _Compare __comp) { return std::max_element(__l.begin(), __l.end(), __comp); } template<typename _Tp> _GLIBCXX14_CONSTEXPR inline pair<_Tp, _Tp> minmax(initializer_list<_Tp> __l) { pair<const _Tp, const _Tp> __p = std::minmax_element(__l.begin(), __l.end()); return std::make_pair(__p.first, __p.second); } template<typename _Tp, typename _Compare> _GLIBCXX14_CONSTEXPR inline pair<_Tp, _Tp> minmax(initializer_list<_Tp> __l, _Compare __comp) { pair<const _Tp, const _Tp> __p = std::minmax_element(__l.begin(), __l.end(), __comp); return std::make_pair(__p.first, __p.second); } template<typename _ForwardIterator1, typename _ForwardIterator2, typename _BinaryPredicate> bool __is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2, _BinaryPredicate __pred) { // Efficiently compare identical prefixes: O(N) if sequences // have the same elements in the same order. for (; __first1 != __last1; ++__first1, (void)++__first2) if (!__pred(__first1, __first2)) break; if (__first1 == __last1) return true; // Establish __last2 assuming equal ranges by iterating over the // rest of the list. _ForwardIterator2 __last2 = __first2; std::advance(__last2, std::distance(__first1, __last1)); for (_ForwardIterator1 __scan = __first1; __scan != __last1; ++__scan) { if (__scan != std::__find_if(__first1, __scan, __gnu_cxx::__ops::__iter_comp_iter(__pred, __scan))) continue; // We've seen this one before. auto __matches = std::__count_if(__first2, __last2, __gnu_cxx::__ops::__iter_comp_iter(__pred, __scan)); if (0 == __matches \|\| std::__count_if(__scan, __last1, __gnu_cxx::__ops::__iter_comp_iter(__pred, __scan)) != __matches) return false; } return true; } /* * @brief Checks whether a permutation of the second sequence is equal * to the first sequence. * @ingroup non_mutating_algorithms * @param __first1 Start of first range. * @param __last1 End of first range. * @param __first2 Start of second range. * @return true if there exists a permutation of the elements in the range * [__first2, __first2 + (__last1 - __first1)), beginning with * ForwardIterator2 begin, such that equal(__first1, __last1, begin) * returns true; otherwise, returns false. / template<typename _ForwardIterator1, typename _ForwardIterator2> inline bool is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2) { // concept requirements __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator1>) __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator2>) __glibcxx_function_requires(_EqualOpConcept< typename iterator_traits<_ForwardIterator1>::value_type, typename iterator_traits<_ForwardIterator2>::value_type>) __glibcxx_requires_valid_range(__first1, __last1); return std::__is_permutation(__first1, __last1, __first2, __gnu_cxx::__ops::__iter_equal_to_iter()); } /* * @brief Checks whether a permutation of the second sequence is equal * to the first sequence. * @ingroup non_mutating_algorithms * @param __first1 Start of first range. * @param __last1 End of first range. * @param __first2 Start of second range. * @param __pred A binary predicate. * @return true if there exists a permutation of the elements in * the range [__first2, __first2 + (__last1 - __first1)), * beginning with ForwardIterator2 begin, such that * equal(__first1, __last1, __begin, __pred) returns true; * otherwise, returns false. / template<typename _ForwardIterator1, typename _ForwardIterator2, typename _BinaryPredicate> inline bool is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2, _BinaryPredicate __pred) { // concept requirements __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator1>) __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator2>) __glibcxx_function_requires(_BinaryPredicateConcept<_BinaryPredicate, typename iterator_traits<_ForwardIterator1>::value_type, typename iterator_traits<_ForwardIterator2>::value_type>) __glibcxx_requires_valid_range(__first1, __last1); return std::__is_permutation(__first1, __last1, __first2, __gnu_cxx::__ops::__iter_comp_iter(__pred)); } #if __cplusplus > 201103L template<typename _ForwardIterator1, typename _ForwardIterator2, typename _BinaryPredicate> bool __is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2, _ForwardIterator2 __last2, _BinaryPredicate __pred) { using _Cat1 = typename iterator_traits<_ForwardIterator1>::iterator_category; using _Cat2 = typename iterator_traits<_ForwardIterator2>::iterator_category; using _It1_is_RA = is_same<_Cat1, random_access_iterator_tag>; using _It2_is_RA = is_same<_Cat2, random_access_iterator_tag>; constexpr bool __ra_iters = _It1_is_RA() && _It2_is_RA(); if (__ra_iters) { auto __d1 = std::distance(__first1, __last1); auto __d2 = std::distance(__first2, __last2); if (__d1 != __d2) return false; } // Efficiently compare identical prefixes: O(N) if sequences // have the same elements in the same order. for (; __first1 != __last1 && __first2 != __last2; ++__first1, (void)++__first2) if (!__pred(__first1, __first2)) break; if (__ra_iters) { if (__first1 == __last1) return true; } else { auto __d1 = std::distance(__first1, __last1); auto __d2 = std::distance(__first2, __last2); if (__d1 == 0 && __d2 == 0) return true; if (__d1 != __d2) return false; } for (_ForwardIterator1 __scan = __first1; __scan != __last1; ++__scan) { if (__scan != std::__find_if(__first1, __scan, __gnu_cxx::__ops::__iter_comp_iter(__pred, __scan))) continue; // We've seen this one before. auto __matches = std::__count_if(__first2, __last2, __gnu_cxx::__ops::__iter_comp_iter(__pred, __scan)); if (0 == __matches \|\| std::__count_if(__scan, __last1, __gnu_cxx::__ops::__iter_comp_iter(__pred, __scan)) != __matches) return false; } return true; } /* * @brief Checks whether a permutaion of the second sequence is equal * to the first sequence. * @ingroup non_mutating_algorithms * @param __first1 Start of first range. * @param __last1 End of first range. * @param __first2 Start of second range. * @param __last2 End of first range. * @return true if there exists a permutation of the elements in the range * [__first2, __last2), beginning with ForwardIterator2 begin, * such that equal(__first1, __last1, begin) returns true; * otherwise, returns false. / template<typename _ForwardIterator1, typename _ForwardIterator2> inline bool is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2, _ForwardIterator2 __last2) { __glibcxx_requires_valid_range(__first1, __last1); __glibcxx_requires_valid_range(__first2, __last2); return std::__is_permutation(__first1, __last1, __first2, __last2, __gnu_cxx::__ops::__iter_equal_to_iter()); } /* * @brief Checks whether a permutation of the second sequence is equal * to the first sequence. * @ingroup non_mutating_algorithms * @param __first1 Start of first range. * @param __last1 End of first range. * @param __first2 Start of second range. * @param __last2 End of first range. * @param __pred A binary predicate. * @return true if there exists a permutation of the elements in the range * [__first2, __last2), beginning with ForwardIterator2 begin, * such that equal(__first1, __last1, __begin, __pred) returns true; * otherwise, returns false. / template<typename _ForwardIterator1, typename _ForwardIterator2, typename _BinaryPredicate> inline bool is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2, _ForwardIterator2 __last2, _BinaryPredicate __pred) { __glibcxx_requires_valid_range(__first1, __last1); __glibcxx_requires_valid_range(__first2, __last2); return std::__is_permutation(__first1, __last1, __first2, __last2, __gnu_cxx::__ops::__iter_comp_iter(__pred)); } #if __cplusplus > 201402L #define __cpp_lib_clamp 201603 /* * @brief Returns the value clamped between lo and hi. * @ingroup sorting_algorithms * @param __val A value of arbitrary type. * @param __lo A lower limit of arbitrary type. * @param __hi An upper limit of arbitrary type. * @return max(__val, __lo) if __val < __hi or min(__val, __hi) otherwise. / template<typename _Tp> constexpr const _Tp& clamp(const _Tp& __val, const _Tp& __lo, const _Tp& __hi) { __glibcxx_assert(!(__hi < __lo)); return (__val < __lo) ? __lo : (__hi < __val) ? __hi : __val; } /* * @brief Returns the value clamped between lo and hi. * @ingroup sorting_algorithms * @param __val A value of arbitrary type. * @param __lo A lower limit of arbitrary type. * @param __hi An upper limit of arbitrary type. * @param __comp A comparison functor. * @return max(__val, __lo, __comp) if __comp(__val, __hi) * or min(__val, __hi, __comp) otherwise. / template<typename _Tp, typename _Compare> constexpr const _Tp& clamp(const _Tp& __val, const _Tp& __lo, const _Tp& __hi, _Compare __comp) { __glibcxx_assert(!__comp(__hi, __lo)); return __comp(__val, __lo) ? __lo : __comp(__hi, __val) ? __hi : __val; } #endif // C++17 #endif // C++14 #ifdef _GLIBCXX_USE_C99_STDINT_TR1 /* * @brief Generate two uniformly distributed integers using a * single distribution invocation. * @param __b0 The upper bound for the first integer. * @param __b1 The upper bound for the second integer. * @param __g A UniformRandomBitGenerator. * @return A pair (i, j) with i and j uniformly distributed * over [0, __b0) and [0, __b1), respectively. * * Requires: __b0 * __b1 <= __g.max() - __g.min(). * * Using uniform_int_distribution with a range that is very * small relative to the range of the generator ends up wasting * potentially expensively generated randomness, since * uniform_int_distribution does not store leftover randomness * between invocations. * * If we know we want two integers in ranges that are sufficiently * small, we can compose the ranges, use a single distribution * invocation, and significantly reduce the waste. / template<typename _IntType, typename _UniformRandomBitGenerator> pair<_IntType, _IntType> __gen_two_uniform_ints(_IntType __b0, _IntType __b1, _UniformRandomBitGenerator&& __g) { _IntType __x = uniform_int_distribution<_IntType>{0, (__b0 __b1) - 1}(__g); return std::make_pair(__x / __b1, __x % __b1); } /** * @brief Shuffle the elements of a sequence using a uniform random * number generator. * @ingroup mutating_algorithms * @param __first A forward iterator. * @param __last A forward iterator. * @param __g A UniformRandomNumberGenerator (26.5.1.3). * @return Nothing. * * Reorders the elements in the range @p [__first,__last) using @p __g to * provide random numbers. / template<typename _RandomAccessIterator, typename _UniformRandomNumberGenerator> void shuffle(_RandomAccessIterator __first, _RandomAccessIterator __last, _UniformRandomNumberGenerator&& __g) { // concept requirements __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept< _RandomAccessIterator>) __glibcxx_requires_valid_range(__first, __last); if (__first == __last) return; typedef typename iterator_traits<_RandomAccessIterator>::difference_type _DistanceType; typedef typename std::make_unsigned<_DistanceType>::type __ud_type; typedef typename std::uniform_int_distribution<__ud_type> __distr_type; typedef typename __distr_type::param_type __p_type; typedef typename remove_reference<_UniformRandomNumberGenerator>::type _Gen; typedef typename common_type<typename _Gen::result_type, __ud_type>::type __uc_type; const __uc_type __urngrange = __g.max() - __g.min(); const __uc_type __urange = __uc_type(__last - __first); if (__urngrange / __urange >= __urange) // I.e. (__urngrange >= __urange __urange) but without wrap issues. { _RandomAccessIterator __i = __first + 1; // Since we know the range isn't empty, an even number of elements // means an uneven number of elements /to swap/, in which case we // do the first one up front: if ((__urange % 2) == 0) { __distr_type __d{0, 1}; std::iter_swap(__i++, __first + __d(__g)); } // Now we know that __last - __i is even, so we do the rest in pairs, // using a single distribution invocation to produce swap positions // for two successive elements at a time: while (__i != __last) { const __uc_type __swap_range = __uc_type(__i - __first) + 1; const pair<__uc_type, __uc_type> __pospos = __gen_two_uniform_ints(__swap_range, __swap_range + 1, __g); std::iter_swap(__i++, __first + __pospos.first); std::iter_swap(__i++, __first + __pospos.second); } return; } __distr_type __d; for (_RandomAccessIterator __i = __first + 1; __i != __last; ++__i) std::iter_swap(__i, __first + __d(__g, __p_type(0, __i - __first))); } #endif #endif // C++11 _GLIBCXX_BEGIN_NAMESPACE_ALGO /** * @brief Apply a function to every element of a sequence. * @ingroup non_mutating_algorithms * @param __first An input iterator. * @param __last An input iterator. * @param __f A unary function object. * @return @p __f * * Applies the function object @p __f to each element in the range * @p [first,last). @p __f must not modify the order of the sequence. * If @p __f has a return value it is ignored. / template<typename _InputIterator, typename _Function> _Function for_each(_InputIterator __first, _InputIterator __last, _Function __f) { // concept requirements __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>) __glibcxx_requires_valid_range(__first, __last); for (; __first != __last; ++__first) __f(__first); return __f; // N.B. [alg.foreach] says std::move(f) but it's redundant. } /** * @brief Find the first occurrence of a value in a sequence. * @ingroup non_mutating_algorithms * @param __first An input iterator. * @param __last An input iterator. * @param __val The value to find. * @return The first iterator @c i in the range @p [__first,__last) * such that @c i == @p __val, or @p __last if no such iterator exists. / template<typename _InputIterator, typename _Tp> inline _InputIterator find(_InputIterator __first, _InputIterator __last, const _Tp& __val) { // concept requirements __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>) __glibcxx_function_requires(_EqualOpConcept< typename iterator_traits<_InputIterator>::value_type, _Tp>) __glibcxx_requires_valid_range(__first, __last); return std::__find_if(__first, __last, __gnu_cxx::__ops::__iter_equals_val(__val)); } /** * @brief Find the first element in a sequence for which a * predicate is true. * @ingroup non_mutating_algorithms * @param __first An input iterator. * @param __last An input iterator. * @param __pred A predicate. * @return The first iterator @c i in the range @p [__first,__last) * such that @p __pred(i) is true, or @p __last if no such iterator exists. / template<typename _InputIterator, typename _Predicate> inline _InputIterator find_if(_InputIterator __first, _InputIterator __last, _Predicate __pred) { // concept requirements __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>) __glibcxx_function_requires(_UnaryPredicateConcept<_Predicate, typename iterator_traits<_InputIterator>::value_type>) __glibcxx_requires_valid_range(__first, __last); return std::__find_if(__first, __last, __gnu_cxx::__ops::__pred_iter(__pred)); } /** * @brief Find element from a set in a sequence. * @ingroup non_mutating_algorithms * @param __first1 Start of range to search. * @param __last1 End of range to search. * @param __first2 Start of match candidates. * @param __last2 End of match candidates. * @return The first iterator @c i in the range * @p [__first1,__last1) such that @c i == @p (i2) such that i2 is an * iterator in [__first2,__last2), or @p __last1 if no such iterator exists. * * Searches the range @p [__first1,__last1) for an element that is * equal to some element in the range [__first2,__last2). If * found, returns an iterator in the range [__first1,__last1), * otherwise returns @p __last1. / template<typename _InputIterator, typename _ForwardIterator> _InputIterator find_first_of(_InputIterator __first1, _InputIterator __last1, _ForwardIterator __first2, _ForwardIterator __last2) { // concept requirements __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>) __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>) __glibcxx_function_requires(_EqualOpConcept< typename iterator_traits<_InputIterator>::value_type, typename iterator_traits<_ForwardIterator>::value_type>) __glibcxx_requires_valid_range(__first1, __last1); __glibcxx_requires_valid_range(__first2, __last2); for (; __first1 != __last1; ++__first1) for (_ForwardIterator __iter = __first2; __iter != __last2; ++__iter) if (__first1 == __iter) return __first1; return __last1; } /* * @brief Find element from a set in a sequence using a predicate. * @ingroup non_mutating_algorithms * @param __first1 Start of range to search. * @param __last1 End of range to search. * @param __first2 Start of match candidates. * @param __last2 End of match candidates. * @param __comp Predicate to use. * @return The first iterator @c i in the range * @p [__first1,__last1) such that @c comp(i, @p (i2)) is true * and i2 is an iterator in [__first2,__last2), or @p __last1 if no * such iterator exists. * * Searches the range @p [__first1,__last1) for an element that is * equal to some element in the range [__first2,__last2). If * found, returns an iterator in the range [__first1,__last1), * otherwise returns @p __last1. / template<typename _InputIterator, typename _ForwardIterator, typename _BinaryPredicate> _InputIterator find_first_of(_InputIterator __first1, _InputIterator __last1, _ForwardIterator __first2, _ForwardIterator __last2, _BinaryPredicate __comp) { // concept requirements __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>) __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>) __glibcxx_function_requires(_BinaryPredicateConcept<_BinaryPredicate, typename iterator_traits<_InputIterator>::value_type, typename iterator_traits<_ForwardIterator>::value_type>) __glibcxx_requires_valid_range(__first1, __last1); __glibcxx_requires_valid_range(__first2, __last2); for (; __first1 != __last1; ++__first1) for (_ForwardIterator __iter = __first2; __iter != __last2; ++__iter) if (__comp(__first1, __iter)) return __first1; return __last1; } /* * @brief Find two adjacent values in a sequence that are equal. * @ingroup non_mutating_algorithms * @param __first A forward iterator. * @param __last A forward iterator. * @return The first iterator @c i such that @c i and @c i+1 are both * valid iterators in @p [__first,__last) and such that @c i == @c (i+1), * or @p __last if no such iterator exists. / template<typename _ForwardIterator> inline _ForwardIterator adjacent_find(_ForwardIterator __first, _ForwardIterator __last) { // concept requirements __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>) __glibcxx_function_requires(_EqualityComparableConcept< typename iterator_traits<_ForwardIterator>::value_type>) __glibcxx_requires_valid_range(__first, __last); return std::__adjacent_find(__first, __last, __gnu_cxx::__ops::__iter_equal_to_iter()); } /* * @brief Find two adjacent values in a sequence using a predicate. * @ingroup non_mutating_algorithms * @param __first A forward iterator. * @param __last A forward iterator. * @param __binary_pred A binary predicate. * @return The first iterator @c i such that @c i and @c i+1 are both * valid iterators in @p [__first,__last) and such that * @p __binary_pred(i,(i+1)) is true, or @p __last if no such iterator * exists. / template<typename _ForwardIterator, typename _BinaryPredicate> inline _ForwardIterator adjacent_find(_ForwardIterator __first, _ForwardIterator __last, _BinaryPredicate __binary_pred) { // concept requirements __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>) __glibcxx_function_requires(_BinaryPredicateConcept<_BinaryPredicate, typename iterator_traits<_ForwardIterator>::value_type, typename iterator_traits<_ForwardIterator>::value_type>) __glibcxx_requires_valid_range(__first, __last); return std::__adjacent_find(__first, __last, __gnu_cxx::__ops::__iter_comp_iter(__binary_pred)); } /* * @brief Count the number of copies of a value in a sequence. * @ingroup non_mutating_algorithms * @param __first An input iterator. * @param __last An input iterator. * @param __value The value to be counted. * @return The number of iterators @c i in the range @p [__first,__last) * for which @c i == @p __value / template<typename _InputIterator, typename _Tp> inline typename iterator_traits<_InputIterator>::difference_type count(_InputIterator __first, _InputIterator __last, const _Tp& __value) { // concept requirements __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>) __glibcxx_function_requires(_EqualOpConcept< typename iterator_traits<_InputIterator>::value_type, _Tp>) __glibcxx_requires_valid_range(__first, __last); return std::__count_if(__first, __last, __gnu_cxx::__ops::__iter_equals_val(__value)); } /** * @brief Count the elements of a sequence for which a predicate is true. * @ingroup non_mutating_algorithms * @param __first An input iterator. * @param __last An input iterator. * @param __pred A predicate. * @return The number of iterators @c i in the range @p [__first,__last) * for which @p __pred(i) is true. / template<typename _InputIterator, typename _Predicate> inline typename iterator_traits<_InputIterator>::difference_type count_if(_InputIterator __first, _InputIterator __last, _Predicate __pred) { // concept requirements __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>) __glibcxx_function_requires(_UnaryPredicateConcept<_Predicate, typename iterator_traits<_InputIterator>::value_type>) __glibcxx_requires_valid_range(__first, __last); return std::__count_if(__first, __last, __gnu_cxx::__ops::__pred_iter(__pred)); } /** * @brief Search a sequence for a matching sub-sequence. * @ingroup non_mutating_algorithms * @param __first1 A forward iterator. * @param __last1 A forward iterator. * @param __first2 A forward iterator. * @param __last2 A forward iterator. * @return The first iterator @c i in the range @p * [__first1,__last1-(__last2-__first2)) such that @c (i+N) == @p (__first2+N) for each @c N in the range @p [0,__last2-__first2), or @p __last1 if no such iterator exists. * * Searches the range @p [__first1,__last1) for a sub-sequence that * compares equal value-by-value with the sequence given by @p * [__first2,__last2) and returns an iterator to the first element * of the sub-sequence, or @p __last1 if the sub-sequence is not * found. * * Because the sub-sequence must lie completely within the range @p * [__first1,__last1) it must start at a position less than @p * __last1-(__last2-__first2) where @p __last2-__first2 is the * length of the sub-sequence. * * This means that the returned iterator @c i will be in the range * @p [__first1,__last1-(__last2-__first2)) / template<typename _ForwardIterator1, typename _ForwardIterator2> inline _ForwardIterator1 search(_ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2, _ForwardIterator2 __last2) { // concept requirements __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator1>) __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator2>) __glibcxx_function_requires(_EqualOpConcept< typename iterator_traits<_ForwardIterator1>::value_type, typename iterator_traits<_ForwardIterator2>::value_type>) __glibcxx_requires_valid_range(__first1, __last1); __glibcxx_requires_valid_range(__first2, __last2); return std::__search(__first1, __last1, __first2, __last2, __gnu_cxx::__ops::__iter_equal_to_iter()); } /* * @brief Search a sequence for a matching sub-sequence using a predicate. * @ingroup non_mutating_algorithms * @param __first1 A forward iterator. * @param __last1 A forward iterator. * @param __first2 A forward iterator. * @param __last2 A forward iterator. * @param __predicate A binary predicate. * @return The first iterator @c i in the range * @p [__first1,__last1-(__last2-__first2)) such that * @p __predicate((i+N),(__first2+N)) is true for each @c N in the range * @p [0,__last2-__first2), or @p __last1 if no such iterator exists. * * Searches the range @p [__first1,__last1) for a sub-sequence that * compares equal value-by-value with the sequence given by @p * [__first2,__last2), using @p __predicate to determine equality, * and returns an iterator to the first element of the * sub-sequence, or @p __last1 if no such iterator exists. * * @see search(_ForwardIter1, _ForwardIter1, _ForwardIter2, _ForwardIter2) / template<typename _ForwardIterator1, typename _ForwardIterator2, typename _BinaryPredicate> inline _ForwardIterator1 search(_ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2, _ForwardIterator2 __last2, _BinaryPredicate __predicate) { // concept requirements __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator1>) __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator2>) __glibcxx_function_requires(_BinaryPredicateConcept<_BinaryPredicate, typename iterator_traits<_ForwardIterator1>::value_type, typename iterator_traits<_ForwardIterator2>::value_type>) __glibcxx_requires_valid_range(__first1, __last1); __glibcxx_requires_valid_range(__first2, __last2); return std::__search(__first1, __last1, __first2, __last2, __gnu_cxx::__ops::__iter_comp_iter(__predicate)); } /* * @brief Search a sequence for a number of consecutive values. * @ingroup non_mutating_algorithms * @param __first A forward iterator. * @param __last A forward iterator. * @param __count The number of consecutive values. * @param __val The value to find. * @return The first iterator @c i in the range @p * [__first,__last-__count) such that @c (i+N) == @p __val for each @c N in the range @p [0,__count), or @p __last if no such * iterator exists. * * Searches the range @p [__first,__last) for @p count consecutive elements * equal to @p __val. / template<typename _ForwardIterator, typename _Integer, typename _Tp> inline _ForwardIterator search_n(_ForwardIterator __first, _ForwardIterator __last, _Integer __count, const _Tp& __val) { // concept requirements __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>) __glibcxx_function_requires(_EqualOpConcept< typename iterator_traits<_ForwardIterator>::value_type, _Tp>) __glibcxx_requires_valid_range(__first, __last); return std::__search_n(__first, __last, __count, __gnu_cxx::__ops::__iter_equals_val(__val)); } /* * @brief Search a sequence for a number of consecutive values using a * predicate. * @ingroup non_mutating_algorithms * @param __first A forward iterator. * @param __last A forward iterator. * @param __count The number of consecutive values. * @param __val The value to find. * @param __binary_pred A binary predicate. * @return The first iterator @c i in the range @p * [__first,__last-__count) such that @p * __binary_pred((i+N),__val) is true for each @c N in the range @p [0,__count), or @p __last if no such iterator exists. * * Searches the range @p [__first,__last) for @p __count * consecutive elements for which the predicate returns true. / template<typename _ForwardIterator, typename _Integer, typename _Tp, typename _BinaryPredicate> inline _ForwardIterator search_n(_ForwardIterator __first, _ForwardIterator __last, _Integer __count, const _Tp& __val, _BinaryPredicate __binary_pred) { // concept requirements __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>) __glibcxx_function_requires(_BinaryPredicateConcept<_BinaryPredicate, typename iterator_traits<_ForwardIterator>::value_type, _Tp>) __glibcxx_requires_valid_range(__first, __last); return std::__search_n(__first, __last, __count, __gnu_cxx::__ops::__iter_comp_val(__binary_pred, __val)); } #if __cplusplus > 201402L /* @brief Search a sequence using a Searcher object. * * @param __first A forward iterator. * @param __last A forward iterator. * @param __searcher A callable object. * @return @p __searcher(__first,__last).first / template<typename _ForwardIterator, typename _Searcher> inline _ForwardIterator search(_ForwardIterator __first, _ForwardIterator __last, const _Searcher& __searcher) { return __searcher(__first, __last).first; } #endif /* * @brief Perform an operation on a sequence. * @ingroup mutating_algorithms * @param __first An input iterator. * @param __last An input iterator. * @param __result An output iterator. * @param __unary_op A unary operator. * @return An output iterator equal to @p __result+(__last-__first). * * Applies the operator to each element in the input range and assigns * the results to successive elements of the output sequence. * Evaluates @p (__result+N)=unary_op((__first+N)) for each @c N in the * range @p [0,__last-__first). * * @p unary_op must not alter its argument. / template<typename _InputIterator, typename _OutputIterator, typename _UnaryOperation> _OutputIterator transform(_InputIterator __first, _InputIterator __last, _OutputIterator __result, _UnaryOperation __unary_op) { // concept requirements __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>) __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator, // "the type returned by a _UnaryOperation" __typeof__(__unary_op(__first))>) __glibcxx_requires_valid_range(__first, __last); for (; __first != __last; ++__first, (void)++__result) __result = __unary_op(__first); return __result; } /** * @brief Perform an operation on corresponding elements of two sequences. * @ingroup mutating_algorithms * @param __first1 An input iterator. * @param __last1 An input iterator. * @param __first2 An input iterator. * @param __result An output iterator. * @param __binary_op A binary operator. * @return An output iterator equal to @p result+(last-first). * * Applies the operator to the corresponding elements in the two * input ranges and assigns the results to successive elements of the * output sequence. * Evaluates @p * (__result+N)=__binary_op((__first1+N),(__first2+N)) for each @c N in the range @p [0,__last1-__first1). * * @p binary_op must not alter either of its arguments. / template<typename _InputIterator1, typename _InputIterator2, typename _OutputIterator, typename _BinaryOperation> _OutputIterator transform(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _OutputIterator __result, _BinaryOperation __binary_op) { // concept requirements __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>) __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>) __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator, // "the type returned by a _BinaryOperation" __typeof__(__binary_op(__first1,__first2))>) __glibcxx_requires_valid_range(__first1, __last1); for (; __first1 != __last1; ++__first1, (void)++__first2, ++__result) __result = __binary_op(__first1, __first2); return __result; } /** * @brief Replace each occurrence of one value in a sequence with another * value. * @ingroup mutating_algorithms * @param __first A forward iterator. * @param __last A forward iterator. * @param __old_value The value to be replaced. * @param __new_value The replacement value. * @return replace() returns no value. * * For each iterator @c i in the range @p [__first,__last) if @c i == @p __old_value then the assignment @c i = @p __new_value is performed. / template<typename _ForwardIterator, typename _Tp> void replace(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __old_value, const _Tp& __new_value) { // concept requirements __glibcxx_function_requires(_Mutable_ForwardIteratorConcept< _ForwardIterator>) __glibcxx_function_requires(_EqualOpConcept< typename iterator_traits<_ForwardIterator>::value_type, _Tp>) __glibcxx_function_requires(_ConvertibleConcept<_Tp, typename iterator_traits<_ForwardIterator>::value_type>) __glibcxx_requires_valid_range(__first, __last); for (; __first != __last; ++__first) if (__first == __old_value) __first = __new_value; } /** * @brief Replace each value in a sequence for which a predicate returns * true with another value. * @ingroup mutating_algorithms * @param __first A forward iterator. * @param __last A forward iterator. * @param __pred A predicate. * @param __new_value The replacement value. * @return replace_if() returns no value. * * For each iterator @c i in the range @p [__first,__last) if @p __pred(i) is true then the assignment @c i = @p __new_value is performed. / template<typename _ForwardIterator, typename _Predicate, typename _Tp> void replace_if(_ForwardIterator __first, _ForwardIterator __last, _Predicate __pred, const _Tp& __new_value) { // concept requirements __glibcxx_function_requires(_Mutable_ForwardIteratorConcept< _ForwardIterator>) __glibcxx_function_requires(_ConvertibleConcept<_Tp, typename iterator_traits<_ForwardIterator>::value_type>) __glibcxx_function_requires(_UnaryPredicateConcept<_Predicate, typename iterator_traits<_ForwardIterator>::value_type>) __glibcxx_requires_valid_range(__first, __last); for (; __first != __last; ++__first) if (__pred(__first)) __first = __new_value; } /** * @brief Assign the result of a function object to each value in a * sequence. * @ingroup mutating_algorithms * @param __first A forward iterator. * @param __last A forward iterator. * @param __gen A function object taking no arguments and returning * std::iterator_traits<_ForwardIterator>::value_type * @return generate() returns no value. * * Performs the assignment @c i = @p __gen() for each @c i in the range @p [__first,__last). / template<typename _ForwardIterator, typename _Generator> void generate(_ForwardIterator __first, _ForwardIterator __last, _Generator __gen) { // concept requirements __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>) __glibcxx_function_requires(_GeneratorConcept<_Generator, typename iterator_traits<_ForwardIterator>::value_type>) __glibcxx_requires_valid_range(__first, __last); for (; __first != __last; ++__first) __first = __gen(); } /** * @brief Assign the result of a function object to each value in a * sequence. * @ingroup mutating_algorithms * @param __first A forward iterator. * @param __n The length of the sequence. * @param __gen A function object taking no arguments and returning * std::iterator_traits<_ForwardIterator>::value_type * @return The end of the sequence, @p __first+__n * * Performs the assignment @c i = @p __gen() for each @c i in the range @p [__first,__first+__n). * * _GLIBCXX_RESOLVE_LIB_DEFECTS * DR 865. More algorithms that throw away information / template<typename _OutputIterator, typename _Size, typename _Generator> _OutputIterator generate_n(_OutputIterator __first, _Size __n, _Generator __gen) { // concept requirements __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator, // "the type returned by a _Generator" __typeof__(__gen())>) for (__decltype(__n + 0) __niter = __n; __niter > 0; --__niter, (void) ++__first) __first = __gen(); return __first; } /** * @brief Copy a sequence, removing consecutive duplicate values. * @ingroup mutating_algorithms * @param __first An input iterator. * @param __last An input iterator. * @param __result An output iterator. * @return An iterator designating the end of the resulting sequence. * * Copies each element in the range @p [__first,__last) to the range * beginning at @p __result, except that only the first element is copied * from groups of consecutive elements that compare equal. * unique_copy() is stable, so the relative order of elements that are * copied is unchanged. * * _GLIBCXX_RESOLVE_LIB_DEFECTS * DR 241. Does unique_copy() require CopyConstructible and Assignable? * * _GLIBCXX_RESOLVE_LIB_DEFECTS * DR 538. 241 again: Does unique_copy() require CopyConstructible and * Assignable? / template<typename _InputIterator, typename _OutputIterator> inline _OutputIterator unique_copy(_InputIterator __first, _InputIterator __last, _OutputIterator __result) { // concept requirements __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>) __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator, typename iterator_traits<_InputIterator>::value_type>) __glibcxx_function_requires(_EqualityComparableConcept< typename iterator_traits<_InputIterator>::value_type>) __glibcxx_requires_valid_range(__first, __last); if (__first == __last) return __result; return std::__unique_copy(__first, __last, __result, __gnu_cxx::__ops::__iter_equal_to_iter(), std::__iterator_category(__first), std::__iterator_category(__result)); } /* * @brief Copy a sequence, removing consecutive values using a predicate. * @ingroup mutating_algorithms * @param __first An input iterator. * @param __last An input iterator. * @param __result An output iterator. * @param __binary_pred A binary predicate. * @return An iterator designating the end of the resulting sequence. * * Copies each element in the range @p [__first,__last) to the range * beginning at @p __result, except that only the first element is copied * from groups of consecutive elements for which @p __binary_pred returns * true. * unique_copy() is stable, so the relative order of elements that are * copied is unchanged. * * _GLIBCXX_RESOLVE_LIB_DEFECTS * DR 241. Does unique_copy() require CopyConstructible and Assignable? / template<typename _InputIterator, typename _OutputIterator, typename _BinaryPredicate> inline _OutputIterator unique_copy(_InputIterator __first, _InputIterator __last, _OutputIterator __result, _BinaryPredicate __binary_pred) { // concept requirements -- predicates checked later __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>) __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator, typename iterator_traits<_InputIterator>::value_type>) __glibcxx_requires_valid_range(__first, __last); if (__first == __last) return __result; return std::__unique_copy(__first, __last, __result, __gnu_cxx::__ops::__iter_comp_iter(__binary_pred), std::__iterator_category(__first), std::__iterator_category(__result)); } #if _GLIBCXX_HOSTED /* * @brief Randomly shuffle the elements of a sequence. * @ingroup mutating_algorithms * @param __first A forward iterator. * @param __last A forward iterator. * @return Nothing. * * Reorder the elements in the range @p [__first,__last) using a random * distribution, so that every possible ordering of the sequence is * equally likely. / template<typename _RandomAccessIterator> inline void random_shuffle(_RandomAccessIterator __first, _RandomAccessIterator __last) { // concept requirements __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept< _RandomAccessIterator>) __glibcxx_requires_valid_range(__first, __last); if (__first != __last) for (_RandomAccessIterator __i = __first + 1; __i != __last; ++__i) { // XXX rand() % N is not uniformly distributed _RandomAccessIterator __j = __first + std::rand() % ((__i - __first) + 1); if (__i != __j) std::iter_swap(__i, __j); } } #endif /* * @brief Shuffle the elements of a sequence using a random number * generator. * @ingroup mutating_algorithms * @param __first A forward iterator. * @param __last A forward iterator. * @param __rand The RNG functor or function. * @return Nothing. * * Reorders the elements in the range @p [__first,__last) using @p __rand to * provide a random distribution. Calling @p __rand(N) for a positive * integer @p N should return a randomly chosen integer from the * range [0,N). / template<typename _RandomAccessIterator, typename _RandomNumberGenerator> void random_shuffle(_RandomAccessIterator __first, _RandomAccessIterator __last, #if __cplusplus >= 201103L _RandomNumberGenerator&& __rand) #else _RandomNumberGenerator& __rand) #endif { // concept requirements __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept< _RandomAccessIterator>) __glibcxx_requires_valid_range(__first, __last); if (__first == __last) return; for (_RandomAccessIterator __i = __first + 1; __i != __last; ++__i) { _RandomAccessIterator __j = __first + __rand((__i - __first) + 1); if (__i != __j) std::iter_swap(__i, __j); } } /* * @brief Move elements for which a predicate is true to the beginning * of a sequence. * @ingroup mutating_algorithms * @param __first A forward iterator. * @param __last A forward iterator. * @param __pred A predicate functor. * @return An iterator @p middle such that @p __pred(i) is true for each * iterator @p i in the range @p [__first,middle) and false for each @p i * in the range @p [middle,__last). * * @p __pred must not modify its operand. @p partition() does not preserve * the relative ordering of elements in each group, use * @p stable_partition() if this is needed. / template<typename _ForwardIterator, typename _Predicate> inline _ForwardIterator partition(_ForwardIterator __first, _ForwardIterator __last, _Predicate __pred) { // concept requirements __glibcxx_function_requires(_Mutable_ForwardIteratorConcept< _ForwardIterator>) __glibcxx_function_requires(_UnaryPredicateConcept<_Predicate, typename iterator_traits<_ForwardIterator>::value_type>) __glibcxx_requires_valid_range(__first, __last); return std::__partition(__first, __last, __pred, std::__iterator_category(__first)); } /* * @brief Sort the smallest elements of a sequence. * @ingroup sorting_algorithms * @param __first An iterator. * @param __middle Another iterator. * @param __last Another iterator. * @return Nothing. * * Sorts the smallest @p (__middle-__first) elements in the range * @p [first,last) and moves them to the range @p [__first,__middle). The * order of the remaining elements in the range @p [__middle,__last) is * undefined. * After the sort if @e i and @e j are iterators in the range * @p [__first,__middle) such that i precedes j and @e k is an iterator in * the range @p [__middle,__last) then j<i and k<i are both false. / template<typename _RandomAccessIterator> inline void partial_sort(_RandomAccessIterator __first, _RandomAccessIterator __middle, _RandomAccessIterator __last) { // concept requirements __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept< _RandomAccessIterator>) __glibcxx_function_requires(_LessThanComparableConcept< typename iterator_traits<_RandomAccessIterator>::value_type>) __glibcxx_requires_valid_range(__first, __middle); __glibcxx_requires_valid_range(__middle, __last); __glibcxx_requires_irreflexive(__first, __last); std::__partial_sort(__first, __middle, __last, __gnu_cxx::__ops::__iter_less_iter()); } /* * @brief Sort the smallest elements of a sequence using a predicate * for comparison. * @ingroup sorting_algorithms * @param __first An iterator. * @param __middle Another iterator. * @param __last Another iterator. * @param __comp A comparison functor. * @return Nothing. * * Sorts the smallest @p (__middle-__first) elements in the range * @p [__first,__last) and moves them to the range @p [__first,__middle). The * order of the remaining elements in the range @p [__middle,__last) is * undefined. * After the sort if @e i and @e j are iterators in the range * @p [__first,__middle) such that i precedes j and @e k is an iterator in * the range @p [__middle,__last) then @p __comp(j,i) and @p __comp(k,i) * are both false. / template<typename _RandomAccessIterator, typename _Compare> inline void partial_sort(_RandomAccessIterator __first, _RandomAccessIterator __middle, _RandomAccessIterator __last, _Compare __comp) { // concept requirements __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept< _RandomAccessIterator>) __glibcxx_function_requires(_BinaryPredicateConcept<_Compare, typename iterator_traits<_RandomAccessIterator>::value_type, typename iterator_traits<_RandomAccessIterator>::value_type>) __glibcxx_requires_valid_range(__first, __middle); __glibcxx_requires_valid_range(__middle, __last); __glibcxx_requires_irreflexive_pred(__first, __last, __comp); std::__partial_sort(__first, __middle, __last, __gnu_cxx::__ops::__iter_comp_iter(__comp)); } /* * @brief Sort a sequence just enough to find a particular position. * @ingroup sorting_algorithms * @param __first An iterator. * @param __nth Another iterator. * @param __last Another iterator. * @return Nothing. * * Rearranges the elements in the range @p [__first,__last) so that @p __nth is the same element that would have been in that position had the * whole sequence been sorted. The elements either side of @p __nth are not completely sorted, but for any iterator @e i in the range * @p [__first,__nth) and any iterator @e j in the range @p [__nth,__last) it * holds that j < i is false. / template<typename _RandomAccessIterator> inline void nth_element(_RandomAccessIterator __first, _RandomAccessIterator __nth, _RandomAccessIterator __last) { // concept requirements __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept< _RandomAccessIterator>) __glibcxx_function_requires(_LessThanComparableConcept< typename iterator_traits<_RandomAccessIterator>::value_type>) __glibcxx_requires_valid_range(__first, __nth); __glibcxx_requires_valid_range(__nth, __last); __glibcxx_requires_irreflexive(__first, __last); if (__first == __last \|\| __nth == __last) return; std::__introselect(__first, __nth, __last, std::__lg(__last - __first) 2, __gnu_cxx::__ops::__iter_less_iter()); } /** * @brief Sort a sequence just enough to find a particular position * using a predicate for comparison. * @ingroup sorting_algorithms * @param __first An iterator. * @param __nth Another iterator. * @param __last Another iterator. * @param __comp A comparison functor. * @return Nothing. * * Rearranges the elements in the range @p [__first,__last) so that @p __nth is the same element that would have been in that position had the * whole sequence been sorted. The elements either side of @p __nth are not completely sorted, but for any iterator @e i in the range * @p [__first,__nth) and any iterator @e j in the range @p [__nth,__last) it * holds that @p __comp(j,i) is false. / template<typename _RandomAccessIterator, typename _Compare> inline void nth_element(_RandomAccessIterator __first, _RandomAccessIterator __nth, _RandomAccessIterator __last, _Compare __comp) { // concept requirements __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept< _RandomAccessIterator>) __glibcxx_function_requires(_BinaryPredicateConcept<_Compare, typename iterator_traits<_RandomAccessIterator>::value_type, typename iterator_traits<_RandomAccessIterator>::value_type>) __glibcxx_requires_valid_range(__first, __nth); __glibcxx_requires_valid_range(__nth, __last); __glibcxx_requires_irreflexive_pred(__first, __last, __comp); if (__first == __last \|\| __nth == __last) return; std::__introselect(__first, __nth, __last, std::__lg(__last - __first) 2, __gnu_cxx::__ops::__iter_comp_iter(__comp)); } /** * @brief Sort the elements of a sequence. * @ingroup sorting_algorithms * @param __first An iterator. * @param __last Another iterator. * @return Nothing. * * Sorts the elements in the range @p [__first,__last) in ascending order, * such that for each iterator @e i in the range @p [__first,__last-1), * (i+1)<i is false. * * The relative ordering of equivalent elements is not preserved, use * @p stable_sort() if this is needed. / template<typename _RandomAccessIterator> inline void sort(_RandomAccessIterator __first, _RandomAccessIterator __last) { // concept requirements __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept< _RandomAccessIterator>) __glibcxx_function_requires(_LessThanComparableConcept< typename iterator_traits<_RandomAccessIterator>::value_type>) __glibcxx_requires_valid_range(__first, __last); __glibcxx_requires_irreflexive(__first, __last); std::__sort(__first, __last, __gnu_cxx::__ops::__iter_less_iter()); } /* * @brief Sort the elements of a sequence using a predicate for comparison. * @ingroup sorting_algorithms * @param __first An iterator. * @param __last Another iterator. * @param __comp A comparison functor. * @return Nothing. * * Sorts the elements in the range @p [__first,__last) in ascending order, * such that @p __comp((i+1),i) is false for every iterator @e i in the * range @p [__first,__last-1). * * The relative ordering of equivalent elements is not preserved, use * @p stable_sort() if this is needed. / template<typename _RandomAccessIterator, typename _Compare> inline void sort(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp) { // concept requirements __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept< _RandomAccessIterator>) __glibcxx_function_requires(_BinaryPredicateConcept<_Compare, typename iterator_traits<_RandomAccessIterator>::value_type, typename iterator_traits<_RandomAccessIterator>::value_type>) __glibcxx_requires_valid_range(__first, __last); __glibcxx_requires_irreflexive_pred(__first, __last, __comp); std::__sort(__first, __last, __gnu_cxx::__ops::__iter_comp_iter(__comp)); } template<typename _InputIterator1, typename _InputIterator2, typename _OutputIterator, typename _Compare> _OutputIterator __merge(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp) { while (__first1 != __last1 && __first2 != __last2) { if (__comp(__first2, __first1)) { __result = __first2; ++__first2; } else { __result = __first1; ++__first1; } ++__result; } return std::copy(__first2, __last2, std::copy(__first1, __last1, __result)); } /* * @brief Merges two sorted ranges. * @ingroup sorting_algorithms * @param __first1 An iterator. * @param __first2 Another iterator. * @param __last1 Another iterator. * @param __last2 Another iterator. * @param __result An iterator pointing to the end of the merged range. * @return An iterator pointing to the first element <em>not less * than</em> @e val. * * Merges the ranges @p [__first1,__last1) and @p [__first2,__last2) into * the sorted range @p [__result, __result + (__last1-__first1) + * (__last2-__first2)). Both input ranges must be sorted, and the * output range must not overlap with either of the input ranges. * The sort is @e stable, that is, for equivalent elements in the * two ranges, elements from the first range will always come * before elements from the second. / template<typename _InputIterator1, typename _InputIterator2, typename _OutputIterator> inline _OutputIterator merge(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result) { // concept requirements __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>) __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>) __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator, typename iterator_traits<_InputIterator1>::value_type>) __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator, typename iterator_traits<_InputIterator2>::value_type>) __glibcxx_function_requires(_LessThanOpConcept< typename iterator_traits<_InputIterator2>::value_type, typename iterator_traits<_InputIterator1>::value_type>) __glibcxx_requires_sorted_set(__first1, __last1, __first2); __glibcxx_requires_sorted_set(__first2, __last2, __first1); __glibcxx_requires_irreflexive2(__first1, __last1); __glibcxx_requires_irreflexive2(__first2, __last2); return _GLIBCXX_STD_A::__merge(__first1, __last1, __first2, __last2, __result, __gnu_cxx::__ops::__iter_less_iter()); } /* * @brief Merges two sorted ranges. * @ingroup sorting_algorithms * @param __first1 An iterator. * @param __first2 Another iterator. * @param __last1 Another iterator. * @param __last2 Another iterator. * @param __result An iterator pointing to the end of the merged range. * @param __comp A functor to use for comparisons. * @return An iterator pointing to the first element "not less * than" @e val. * * Merges the ranges @p [__first1,__last1) and @p [__first2,__last2) into * the sorted range @p [__result, __result + (__last1-__first1) + * (__last2-__first2)). Both input ranges must be sorted, and the * output range must not overlap with either of the input ranges. * The sort is @e stable, that is, for equivalent elements in the * two ranges, elements from the first range will always come * before elements from the second. * * The comparison function should have the same effects on ordering as * the function used for the initial sort. / template<typename _InputIterator1, typename _InputIterator2, typename _OutputIterator, typename _Compare> inline _OutputIterator merge(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp) { // concept requirements __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>) __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>) __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator, typename iterator_traits<_InputIterator1>::value_type>) __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator, typename iterator_traits<_InputIterator2>::value_type>) __glibcxx_function_requires(_BinaryPredicateConcept<_Compare, typename iterator_traits<_InputIterator2>::value_type, typename iterator_traits<_InputIterator1>::value_type>) __glibcxx_requires_sorted_set_pred(__first1, __last1, __first2, __comp); __glibcxx_requires_sorted_set_pred(__first2, __last2, __first1, __comp); __glibcxx_requires_irreflexive_pred2(__first1, __last1, __comp); __glibcxx_requires_irreflexive_pred2(__first2, __last2, __comp); return _GLIBCXX_STD_A::__merge(__first1, __last1, __first2, __last2, __result, __gnu_cxx::__ops::__iter_comp_iter(__comp)); } template<typename _RandomAccessIterator, typename _Compare> inline void __stable_sort(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp) { typedef typename iterator_traits<_RandomAccessIterator>::value_type _ValueType; typedef typename iterator_traits<_RandomAccessIterator>::difference_type _DistanceType; typedef _Temporary_buffer<_RandomAccessIterator, _ValueType> _TmpBuf; _TmpBuf __buf(__first, __last); if (__buf.begin() == 0) std::__inplace_stable_sort(__first, __last, __comp); else std::__stable_sort_adaptive(__first, __last, __buf.begin(), _DistanceType(__buf.size()), __comp); } /* * @brief Sort the elements of a sequence, preserving the relative order * of equivalent elements. * @ingroup sorting_algorithms * @param __first An iterator. * @param __last Another iterator. * @return Nothing. * * Sorts the elements in the range @p [__first,__last) in ascending order, * such that for each iterator @p i in the range @p [__first,__last-1), * @p (i+1)<i is false. * * The relative ordering of equivalent elements is preserved, so any two * elements @p x and @p y in the range @p [__first,__last) such that * @p x<y is false and @p y<x is false will have the same relative * ordering after calling @p stable_sort(). / template<typename _RandomAccessIterator> inline void stable_sort(_RandomAccessIterator __first, _RandomAccessIterator __last) { // concept requirements __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept< _RandomAccessIterator>) __glibcxx_function_requires(_LessThanComparableConcept< typename iterator_traits<_RandomAccessIterator>::value_type>) __glibcxx_requires_valid_range(__first, __last); __glibcxx_requires_irreflexive(__first, __last); _GLIBCXX_STD_A::__stable_sort(__first, __last, __gnu_cxx::__ops::__iter_less_iter()); } /* * @brief Sort the elements of a sequence using a predicate for comparison, * preserving the relative order of equivalent elements. * @ingroup sorting_algorithms * @param __first An iterator. * @param __last Another iterator. * @param __comp A comparison functor. * @return Nothing. * * Sorts the elements in the range @p [__first,__last) in ascending order, * such that for each iterator @p i in the range @p [__first,__last-1), * @p __comp((i+1),i) is false. * * The relative ordering of equivalent elements is preserved, so any two * elements @p x and @p y in the range @p [__first,__last) such that * @p __comp(x,y) is false and @p __comp(y,x) is false will have the same * relative ordering after calling @p stable_sort(). / template<typename _RandomAccessIterator, typename _Compare> inline void stable_sort(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp) { // concept requirements __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept< _RandomAccessIterator>) __glibcxx_function_requires(_BinaryPredicateConcept<_Compare, typename iterator_traits<_RandomAccessIterator>::value_type, typename iterator_traits<_RandomAccessIterator>::value_type>) __glibcxx_requires_valid_range(__first, __last); __glibcxx_requires_irreflexive_pred(__first, __last, __comp); _GLIBCXX_STD_A::__stable_sort(__first, __last, __gnu_cxx::__ops::__iter_comp_iter(__comp)); } template<typename _InputIterator1, typename _InputIterator2, typename _OutputIterator, typename _Compare> _OutputIterator __set_union(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp) { while (__first1 != __last1 && __first2 != __last2) { if (__comp(__first1, __first2)) { __result = __first1; ++__first1; } else if (__comp(__first2, __first1)) { __result = __first2; ++__first2; } else { __result = __first1; ++__first1; ++__first2; } ++__result; } return std::copy(__first2, __last2, std::copy(__first1, __last1, __result)); } /* * @brief Return the union of two sorted ranges. * @ingroup set_algorithms * @param __first1 Start of first range. * @param __last1 End of first range. * @param __first2 Start of second range. * @param __last2 End of second range. * @param __result Start of output range. * @return End of the output range. * @ingroup set_algorithms * * This operation iterates over both ranges, copying elements present in * each range in order to the output range. Iterators increment for each * range. When the current element of one range is less than the other, * that element is copied and the iterator advanced. If an element is * contained in both ranges, the element from the first range is copied and * both ranges advance. The output range may not overlap either input * range. / template<typename _InputIterator1, typename _InputIterator2, typename _OutputIterator> inline _OutputIterator set_union(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result) { // concept requirements __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>) __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>) __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator, typename iterator_traits<_InputIterator1>::value_type>) __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator, typename iterator_traits<_InputIterator2>::value_type>) __glibcxx_function_requires(_LessThanOpConcept< typename iterator_traits<_InputIterator1>::value_type, typename iterator_traits<_InputIterator2>::value_type>) __glibcxx_function_requires(_LessThanOpConcept< typename iterator_traits<_InputIterator2>::value_type, typename iterator_traits<_InputIterator1>::value_type>) __glibcxx_requires_sorted_set(__first1, __last1, __first2); __glibcxx_requires_sorted_set(__first2, __last2, __first1); __glibcxx_requires_irreflexive2(__first1, __last1); __glibcxx_requires_irreflexive2(__first2, __last2); return _GLIBCXX_STD_A::__set_union(__first1, __last1, __first2, __last2, __result, __gnu_cxx::__ops::__iter_less_iter()); } /* * @brief Return the union of two sorted ranges using a comparison functor. * @ingroup set_algorithms * @param __first1 Start of first range. * @param __last1 End of first range. * @param __first2 Start of second range. * @param __last2 End of second range. * @param __result Start of output range. * @param __comp The comparison functor. * @return End of the output range. * @ingroup set_algorithms * * This operation iterates over both ranges, copying elements present in * each range in order to the output range. Iterators increment for each * range. When the current element of one range is less than the other * according to @p __comp, that element is copied and the iterator advanced. * If an equivalent element according to @p __comp is contained in both * ranges, the element from the first range is copied and both ranges * advance. The output range may not overlap either input range. / template<typename _InputIterator1, typename _InputIterator2, typename _OutputIterator, typename _Compare> inline _OutputIterator set_union(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp) { // concept requirements __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>) __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>) __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator, typename iterator_traits<_InputIterator1>::value_type>) __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator, typename iterator_traits<_InputIterator2>::value_type>) __glibcxx_function_requires(_BinaryPredicateConcept<_Compare, typename iterator_traits<_InputIterator1>::value_type, typename iterator_traits<_InputIterator2>::value_type>) __glibcxx_function_requires(_BinaryPredicateConcept<_Compare, typename iterator_traits<_InputIterator2>::value_type, typename iterator_traits<_InputIterator1>::value_type>) __glibcxx_requires_sorted_set_pred(__first1, __last1, __first2, __comp); __glibcxx_requires_sorted_set_pred(__first2, __last2, __first1, __comp); __glibcxx_requires_irreflexive_pred2(__first1, __last1, __comp); __glibcxx_requires_irreflexive_pred2(__first2, __last2, __comp); return _GLIBCXX_STD_A::__set_union(__first1, __last1, __first2, __last2, __result, __gnu_cxx::__ops::__iter_comp_iter(__comp)); } template<typename _InputIterator1, typename _InputIterator2, typename _OutputIterator, typename _Compare> _OutputIterator __set_intersection(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp) { while (__first1 != __last1 && __first2 != __last2) if (__comp(__first1, __first2)) ++__first1; else if (__comp(__first2, __first1)) ++__first2; else { __result = __first1; ++__first1; ++__first2; ++__result; } return __result; } /* * @brief Return the intersection of two sorted ranges. * @ingroup set_algorithms * @param __first1 Start of first range. * @param __last1 End of first range. * @param __first2 Start of second range. * @param __last2 End of second range. * @param __result Start of output range. * @return End of the output range. * @ingroup set_algorithms * * This operation iterates over both ranges, copying elements present in * both ranges in order to the output range. Iterators increment for each * range. When the current element of one range is less than the other, * that iterator advances. If an element is contained in both ranges, the * element from the first range is copied and both ranges advance. The * output range may not overlap either input range. / template<typename _InputIterator1, typename _InputIterator2, typename _OutputIterator> inline _OutputIterator set_intersection(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result) { // concept requirements __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>) __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>) __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator, typename iterator_traits<_InputIterator1>::value_type>) __glibcxx_function_requires(_LessThanOpConcept< typename iterator_traits<_InputIterator1>::value_type, typename iterator_traits<_InputIterator2>::value_type>) __glibcxx_function_requires(_LessThanOpConcept< typename iterator_traits<_InputIterator2>::value_type, typename iterator_traits<_InputIterator1>::value_type>) __glibcxx_requires_sorted_set(__first1, __last1, __first2); __glibcxx_requires_sorted_set(__first2, __last2, __first1); __glibcxx_requires_irreflexive2(__first1, __last1); __glibcxx_requires_irreflexive2(__first2, __last2); return _GLIBCXX_STD_A::__set_intersection(__first1, __last1, __first2, __last2, __result, __gnu_cxx::__ops::__iter_less_iter()); } /* * @brief Return the intersection of two sorted ranges using comparison * functor. * @ingroup set_algorithms * @param __first1 Start of first range. * @param __last1 End of first range. * @param __first2 Start of second range. * @param __last2 End of second range. * @param __result Start of output range. * @param __comp The comparison functor. * @return End of the output range. * @ingroup set_algorithms * * This operation iterates over both ranges, copying elements present in * both ranges in order to the output range. Iterators increment for each * range. When the current element of one range is less than the other * according to @p __comp, that iterator advances. If an element is * contained in both ranges according to @p __comp, the element from the * first range is copied and both ranges advance. The output range may not * overlap either input range. / template<typename _InputIterator1, typename _InputIterator2, typename _OutputIterator, typename _Compare> inline _OutputIterator set_intersection(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp) { // concept requirements __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>) __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>) __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator, typename iterator_traits<_InputIterator1>::value_type>) __glibcxx_function_requires(_BinaryPredicateConcept<_Compare, typename iterator_traits<_InputIterator1>::value_type, typename iterator_traits<_InputIterator2>::value_type>) __glibcxx_function_requires(_BinaryPredicateConcept<_Compare, typename iterator_traits<_InputIterator2>::value_type, typename iterator_traits<_InputIterator1>::value_type>) __glibcxx_requires_sorted_set_pred(__first1, __last1, __first2, __comp); __glibcxx_requires_sorted_set_pred(__first2, __last2, __first1, __comp); __glibcxx_requires_irreflexive_pred2(__first1, __last1, __comp); __glibcxx_requires_irreflexive_pred2(__first2, __last2, __comp); return _GLIBCXX_STD_A::__set_intersection(__first1, __last1, __first2, __last2, __result, __gnu_cxx::__ops::__iter_comp_iter(__comp)); } template<typename _InputIterator1, typename _InputIterator2, typename _OutputIterator, typename _Compare> _OutputIterator __set_difference(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp) { while (__first1 != __last1 && __first2 != __last2) if (__comp(__first1, __first2)) { __result = __first1; ++__first1; ++__result; } else if (__comp(__first2, __first1)) ++__first2; else { ++__first1; ++__first2; } return std::copy(__first1, __last1, __result); } /* * @brief Return the difference of two sorted ranges. * @ingroup set_algorithms * @param __first1 Start of first range. * @param __last1 End of first range. * @param __first2 Start of second range. * @param __last2 End of second range. * @param __result Start of output range. * @return End of the output range. * @ingroup set_algorithms * * This operation iterates over both ranges, copying elements present in * the first range but not the second in order to the output range. * Iterators increment for each range. When the current element of the * first range is less than the second, that element is copied and the * iterator advances. If the current element of the second range is less, * the iterator advances, but no element is copied. If an element is * contained in both ranges, no elements are copied and both ranges * advance. The output range may not overlap either input range. / template<typename _InputIterator1, typename _InputIterator2, typename _OutputIterator> inline _OutputIterator set_difference(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result) { // concept requirements __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>) __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>) __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator, typename iterator_traits<_InputIterator1>::value_type>) __glibcxx_function_requires(_LessThanOpConcept< typename iterator_traits<_InputIterator1>::value_type, typename iterator_traits<_InputIterator2>::value_type>) __glibcxx_function_requires(_LessThanOpConcept< typename iterator_traits<_InputIterator2>::value_type, typename iterator_traits<_InputIterator1>::value_type>) __glibcxx_requires_sorted_set(__first1, __last1, __first2); __glibcxx_requires_sorted_set(__first2, __last2, __first1); __glibcxx_requires_irreflexive2(__first1, __last1); __glibcxx_requires_irreflexive2(__first2, __last2); return _GLIBCXX_STD_A::__set_difference(__first1, __last1, __first2, __last2, __result, __gnu_cxx::__ops::__iter_less_iter()); } /* * @brief Return the difference of two sorted ranges using comparison * functor. * @ingroup set_algorithms * @param __first1 Start of first range. * @param __last1 End of first range. * @param __first2 Start of second range. * @param __last2 End of second range. * @param __result Start of output range. * @param __comp The comparison functor. * @return End of the output range. * @ingroup set_algorithms * * This operation iterates over both ranges, copying elements present in * the first range but not the second in order to the output range. * Iterators increment for each range. When the current element of the * first range is less than the second according to @p __comp, that element * is copied and the iterator advances. If the current element of the * second range is less, no element is copied and the iterator advances. * If an element is contained in both ranges according to @p __comp, no * elements are copied and both ranges advance. The output range may not * overlap either input range. / template<typename _InputIterator1, typename _InputIterator2, typename _OutputIterator, typename _Compare> inline _OutputIterator set_difference(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp) { // concept requirements __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>) __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>) __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator, typename iterator_traits<_InputIterator1>::value_type>) __glibcxx_function_requires(_BinaryPredicateConcept<_Compare, typename iterator_traits<_InputIterator1>::value_type, typename iterator_traits<_InputIterator2>::value_type>) __glibcxx_function_requires(_BinaryPredicateConcept<_Compare, typename iterator_traits<_InputIterator2>::value_type, typename iterator_traits<_InputIterator1>::value_type>) __glibcxx_requires_sorted_set_pred(__first1, __last1, __first2, __comp); __glibcxx_requires_sorted_set_pred(__first2, __last2, __first1, __comp); __glibcxx_requires_irreflexive_pred2(__first1, __last1, __comp); __glibcxx_requires_irreflexive_pred2(__first2, __last2, __comp); return _GLIBCXX_STD_A::__set_difference(__first1, __last1, __first2, __last2, __result, __gnu_cxx::__ops::__iter_comp_iter(__comp)); } template<typename _InputIterator1, typename _InputIterator2, typename _OutputIterator, typename _Compare> _OutputIterator __set_symmetric_difference(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp) { while (__first1 != __last1 && __first2 != __last2) if (__comp(__first1, __first2)) { __result = __first1; ++__first1; ++__result; } else if (__comp(__first2, __first1)) { __result = __first2; ++__first2; ++__result; } else { ++__first1; ++__first2; } return std::copy(__first2, __last2, std::copy(__first1, __last1, __result)); } /* * @brief Return the symmetric difference of two sorted ranges. * @ingroup set_algorithms * @param __first1 Start of first range. * @param __last1 End of first range. * @param __first2 Start of second range. * @param __last2 End of second range. * @param __result Start of output range. * @return End of the output range. * @ingroup set_algorithms * * This operation iterates over both ranges, copying elements present in * one range but not the other in order to the output range. Iterators * increment for each range. When the current element of one range is less * than the other, that element is copied and the iterator advances. If an * element is contained in both ranges, no elements are copied and both * ranges advance. The output range may not overlap either input range. / template<typename _InputIterator1, typename _InputIterator2, typename _OutputIterator> inline _OutputIterator set_symmetric_difference(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result) { // concept requirements __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>) __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>) __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator, typename iterator_traits<_InputIterator1>::value_type>) __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator, typename iterator_traits<_InputIterator2>::value_type>) __glibcxx_function_requires(_LessThanOpConcept< typename iterator_traits<_InputIterator1>::value_type, typename iterator_traits<_InputIterator2>::value_type>) __glibcxx_function_requires(_LessThanOpConcept< typename iterator_traits<_InputIterator2>::value_type, typename iterator_traits<_InputIterator1>::value_type>) __glibcxx_requires_sorted_set(__first1, __last1, __first2); __glibcxx_requires_sorted_set(__first2, __last2, __first1); __glibcxx_requires_irreflexive2(__first1, __last1); __glibcxx_requires_irreflexive2(__first2, __last2); return _GLIBCXX_STD_A::__set_symmetric_difference(__first1, __last1, __first2, __last2, __result, __gnu_cxx::__ops::__iter_less_iter()); } /* * @brief Return the symmetric difference of two sorted ranges using * comparison functor. * @ingroup set_algorithms * @param __first1 Start of first range. * @param __last1 End of first range. * @param __first2 Start of second range. * @param __last2 End of second range. * @param __result Start of output range. * @param __comp The comparison functor. * @return End of the output range. * @ingroup set_algorithms * * This operation iterates over both ranges, copying elements present in * one range but not the other in order to the output range. Iterators * increment for each range. When the current element of one range is less * than the other according to @p comp, that element is copied and the * iterator advances. If an element is contained in both ranges according * to @p __comp, no elements are copied and both ranges advance. The output * range may not overlap either input range. / template<typename _InputIterator1, typename _InputIterator2, typename _OutputIterator, typename _Compare> inline _OutputIterator set_symmetric_difference(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp) { // concept requirements __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>) __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>) __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator, typename iterator_traits<_InputIterator1>::value_type>) __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator, typename iterator_traits<_InputIterator2>::value_type>) __glibcxx_function_requires(_BinaryPredicateConcept<_Compare, typename iterator_traits<_InputIterator1>::value_type, typename iterator_traits<_InputIterator2>::value_type>) __glibcxx_function_requires(_BinaryPredicateConcept<_Compare, typename iterator_traits<_InputIterator2>::value_type, typename iterator_traits<_InputIterator1>::value_type>) __glibcxx_requires_sorted_set_pred(__first1, __last1, __first2, __comp); __glibcxx_requires_sorted_set_pred(__first2, __last2, __first1, __comp); __glibcxx_requires_irreflexive_pred2(__first1, __last1, __comp); __glibcxx_requires_irreflexive_pred2(__first2, __last2, __comp); return _GLIBCXX_STD_A::__set_symmetric_difference(__first1, __last1, __first2, __last2, __result, __gnu_cxx::__ops::__iter_comp_iter(__comp)); } template<typename _ForwardIterator, typename _Compare> _GLIBCXX14_CONSTEXPR _ForwardIterator __min_element(_ForwardIterator __first, _ForwardIterator __last, _Compare __comp) { if (__first == __last) return __first; _ForwardIterator __result = __first; while (++__first != __last) if (__comp(__first, __result)) __result = __first; return __result; } /* * @brief Return the minimum element in a range. * @ingroup sorting_algorithms * @param __first Start of range. * @param __last End of range. * @return Iterator referencing the first instance of the smallest value. / template<typename _ForwardIterator> _GLIBCXX14_CONSTEXPR _ForwardIterator inline min_element(_ForwardIterator __first, _ForwardIterator __last) { // concept requirements __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>) __glibcxx_function_requires(_LessThanComparableConcept< typename iterator_traits<_ForwardIterator>::value_type>) __glibcxx_requires_valid_range(__first, __last); __glibcxx_requires_irreflexive(__first, __last); return _GLIBCXX_STD_A::__min_element(__first, __last, __gnu_cxx::__ops::__iter_less_iter()); } /* * @brief Return the minimum element in a range using comparison functor. * @ingroup sorting_algorithms * @param __first Start of range. * @param __last End of range. * @param __comp Comparison functor. * @return Iterator referencing the first instance of the smallest value * according to __comp. / template<typename _ForwardIterator, typename _Compare> _GLIBCXX14_CONSTEXPR inline _ForwardIterator min_element(_ForwardIterator __first, _ForwardIterator __last, _Compare __comp) { // concept requirements __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>) __glibcxx_function_requires(_BinaryPredicateConcept<_Compare, typename iterator_traits<_ForwardIterator>::value_type, typename iterator_traits<_ForwardIterator>::value_type>) __glibcxx_requires_valid_range(__first, __last); __glibcxx_requires_irreflexive_pred(__first, __last, __comp); return _GLIBCXX_STD_A::__min_element(__first, __last, __gnu_cxx::__ops::__iter_comp_iter(__comp)); } template<typename _ForwardIterator, typename _Compare> _GLIBCXX14_CONSTEXPR _ForwardIterator __max_element(_ForwardIterator __first, _ForwardIterator __last, _Compare __comp) { if (__first == __last) return __first; _ForwardIterator __result = __first; while (++__first != __last) if (__comp(__result, __first)) __result = __first; return __result; } /* * @brief Return the maximum element in a range. * @ingroup sorting_algorithms * @param __first Start of range. * @param __last End of range. * @return Iterator referencing the first instance of the largest value. / template<typename _ForwardIterator> _GLIBCXX14_CONSTEXPR inline _ForwardIterator max_element(_ForwardIterator __first, _ForwardIterator __last) { // concept requirements __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>) __glibcxx_function_requires(_LessThanComparableConcept< typename iterator_traits<_ForwardIterator>::value_type>) __glibcxx_requires_valid_range(__first, __last); __glibcxx_requires_irreflexive(__first, __last); return _GLIBCXX_STD_A::__max_element(__first, __last, __gnu_cxx::__ops::__iter_less_iter()); } /* * @brief Return the maximum element in a range using comparison functor. * @ingroup sorting_algorithms * @param __first Start of range. * @param __last End of range. * @param __comp Comparison functor. * @return Iterator referencing the first instance of the largest value * according to __comp. / template<typename _ForwardIterator, typename _Compare> _GLIBCXX14_CONSTEXPR inline _ForwardIterator max_element(_ForwardIterator __first, _ForwardIterator __last, _Compare __comp) { // concept requirements __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>) __glibcxx_function_requires(_BinaryPredicateConcept<_Compare, typename iterator_traits<_ForwardIterator>::value_type, typename iterator_traits<_ForwardIterator>::value_type>) __glibcxx_requires_valid_range(__first, __last); __glibcxx_requires_irreflexive_pred(__first, __last, __comp); return _GLIBCXX_STD_A::__max_element(__first, __last, __gnu_cxx::__ops::__iter_comp_iter(__comp)); } #if __cplusplus >= 201402L /// Reservoir sampling algorithm. template<typename _InputIterator, typename _RandomAccessIterator, typename _Size, typename _UniformRandomBitGenerator> _RandomAccessIterator __sample(_InputIterator __first, _InputIterator __last, input_iterator_tag, _RandomAccessIterator __out, random_access_iterator_tag, _Size __n, _UniformRandomBitGenerator&& __g) { using __distrib_type = uniform_int_distribution<_Size>; using __param_type = typename __distrib_type::param_type; __distrib_type __d{}; _Size __sample_sz = 0; while (__first != __last && __sample_sz != __n) { __out[__sample_sz++] = __first; ++__first; } for (auto __pop_sz = __sample_sz; __first != __last; ++__first, (void) ++__pop_sz) { const auto __k = __d(__g, __param_type{0, __pop_sz}); if (__k < __n) __out[__k] = __first; } return __out + __sample_sz; } /// Selection sampling algorithm. template<typename _ForwardIterator, typename _OutputIterator, typename _Cat, typename _Size, typename _UniformRandomBitGenerator> _OutputIterator __sample(_ForwardIterator __first, _ForwardIterator __last, forward_iterator_tag, _OutputIterator __out, _Cat, _Size __n, _UniformRandomBitGenerator&& __g) { using __distrib_type = uniform_int_distribution<_Size>; using __param_type = typename __distrib_type::param_type; using _USize = make_unsigned_t<_Size>; using _Gen = remove_reference_t<_UniformRandomBitGenerator>; using __uc_type = common_type_t<typename _Gen::result_type, _USize>; if (__first == __last) return __out; __distrib_type __d{}; _Size __unsampled_sz = std::distance(__first, __last); __n = std::min(__n, __unsampled_sz); // If possible, we use __gen_two_uniform_ints to efficiently produce // two random numbers using a single distribution invocation: const __uc_type __urngrange = __g.max() - __g.min(); if (__urngrange / __uc_type(__unsampled_sz) >= __uc_type(__unsampled_sz)) // I.e. (__urngrange >= __unsampled_sz __unsampled_sz) but without // wrapping issues. { while (__n != 0 && __unsampled_sz >= 2) { const pair<_Size, _Size> __p = __gen_two_uniform_ints(__unsampled_sz, __unsampled_sz - 1, __g); --__unsampled_sz; if (__p.first < __n) { __out++ = __first; --__n; } ++__first; if (__n == 0) break; --__unsampled_sz; if (__p.second < __n) { __out++ = __first; --__n; } ++__first; } } // The loop above is otherwise equivalent to this one-at-a-time version: for (; __n != 0; ++__first) if (__d(__g, __param_type{0, --__unsampled_sz}) < __n) { __out++ = __first; --__n; } return __out; } #if __cplusplus > 201402L #define __cpp_lib_sample 201603 /// Take a random sample from a population. template<typename _PopulationIterator, typename _SampleIterator, typename _Distance, typename _UniformRandomBitGenerator> _SampleIterator sample(_PopulationIterator __first, _PopulationIterator __last, _SampleIterator __out, _Distance __n, _UniformRandomBitGenerator&& __g) { using __pop_cat = typename std::iterator_traits<_PopulationIterator>::iterator_category; using __samp_cat = typename std::iterator_traits<_SampleIterator>::iterator_category; static_assert( __or_<is_convertible<__pop_cat, forward_iterator_tag>, is_convertible<__samp_cat, random_access_iterator_tag>>::value, "output range must use a RandomAccessIterator when input range" " does not meet the ForwardIterator requirements"); static_assert(is_integral<_Distance>::value, "sample size must be an integer type"); typename iterator_traits<_PopulationIterator>::difference_type __d = __n; return _GLIBCXX_STD_A:: __sample(__first, __last, __pop_cat{}, __out, __samp_cat{}, __d, std::forward<_UniformRandomBitGenerator>(__g)); } #endif // C++17 #endif // C++14 _GLIBCXX_END_NAMESPACE_ALGO _GLIBCXX_END_NAMESPACE_VERSION } // namespace std #endif /* _STL_ALGO_H */ Back

Edit File : stl_algo.h | Size : 209.27 KB

// Algorithm implementation -*- C++ -*-

// Copyright (C) 2001-2018 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library.  This library is free
// software; you can redistribute it and/or modify it under the
// terms of the GNU General Public License as published by the
// Free Software Foundation; either version 3, or (at your option)
// any later version.

// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// Under Section 7 of GPL version 3, you are granted additional
// permissions described in the GCC Runtime Library Exception, version
// 3.1, as published by the Free Software Foundation.

// You should have received a copy of the GNU General Public License and
// a copy of the GCC Runtime Library Exception along with this program;
// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
// <http://www.gnu.org/licenses/>.

/*
 *
 * Copyright (c) 1994
 * Hewlett-Packard Company
 *
 * Permission to use, copy, modify, distribute and sell this software
 * and its documentation for any purpose is hereby granted without fee,
 * provided that the above copyright notice appear in all copies and
 * that both that copyright notice and this permission notice appear
 * in supporting documentation.  Hewlett-Packard Company makes no
 * representations about the suitability of this software for any
 * purpose.  It is provided "as is" without express or implied warranty.
 *
 *
 * Copyright (c) 1996
 * Silicon Graphics Computer Systems, Inc.
 *
 * Permission to use, copy, modify, distribute and sell this software
 * and its documentation for any purpose is hereby granted without fee,
 * provided that the above copyright notice appear in all copies and
 * that both that copyright notice and this permission notice appear
 * in supporting documentation.  Silicon Graphics makes no
 * representations about the suitability of this software for any
 * purpose.  It is provided "as is" without express or implied warranty.
 */

/** @file bits/stl_algo.h
 *  This is an internal header file, included by other library headers.
 *  Do not attempt to use it directly. @headername{algorithm}
 */

#ifndef _STL_ALGO_H
#define _STL_ALGO_H 1

#include <cstdlib>	     // for rand
#include <bits/algorithmfwd.h>
#include <bits/stl_heap.h>
#include <bits/stl_tempbuf.h>  // for _Temporary_buffer
#include <bits/predefined_ops.h>

#if __cplusplus >= 201103L
#include <bits/uniform_int_dist.h>
#endif

// See concept_check.h for the __glibcxx_*_requires macros.

namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION

/// Swaps the median value of *__a, *__b and *__c under __comp to *__result
  template<typename _Iterator, typename _Compare>
    void
    __move_median_to_first(_Iterator __result,_Iterator __a, _Iterator __b,
			   _Iterator __c, _Compare __comp)
    {
      if (__comp(__a, __b))
	{
	  if (__comp(__b, __c))
	    std::iter_swap(__result, __b);
	  else if (__comp(__a, __c))
	    std::iter_swap(__result, __c);
	  else
	    std::iter_swap(__result, __a);
	}
      else if (__comp(__a, __c))
	std::iter_swap(__result, __a);
      else if (__comp(__b, __c))
	std::iter_swap(__result, __c);
      else
	std::iter_swap(__result, __b);
    }

/// This is an overload used by find algos for the Input Iterator case.
  template<typename _InputIterator, typename _Predicate>
    inline _InputIterator
    __find_if(_InputIterator __first, _InputIterator __last,
	      _Predicate __pred, input_iterator_tag)
    {
      while (__first != __last && !__pred(__first))
	++__first;
      return __first;
    }

/// This is an overload used by find algos for the RAI case.
  template<typename _RandomAccessIterator, typename _Predicate>
    _RandomAccessIterator
    __find_if(_RandomAccessIterator __first, _RandomAccessIterator __last,
	      _Predicate __pred, random_access_iterator_tag)
    {
      typename iterator_traits<_RandomAccessIterator>::difference_type
	__trip_count = (__last - __first) >> 2;

for (; __trip_count > 0; --__trip_count)
	{
	  if (__pred(__first))
	    return __first;
	  ++__first;

if (__pred(__first))
	    return __first;
	  ++__first;

if (__pred(__first))
	    return __first;
	  ++__first;
	}

switch (__last - __first)
	{
	case 3:
	  if (__pred(__first))
	    return __first;
	  ++__first;
	case 2:
	  if (__pred(__first))
	    return __first;
	  ++__first;
	case 1:
	  if (__pred(__first))
	    return __first;
	  ++__first;
	case 0:
	default:
	  return __last;
	}
    }

template<typename _Iterator, typename _Predicate>
    inline _Iterator
    __find_if(_Iterator __first, _Iterator __last, _Predicate __pred)
    {
      return __find_if(__first, __last, __pred,
		       std::__iterator_category(__first));
    }

/// Provided for stable_partition to use.
  template<typename _InputIterator, typename _Predicate>
    inline _InputIterator
    __find_if_not(_InputIterator __first, _InputIterator __last,
		  _Predicate __pred)
    {
      return std::__find_if(__first, __last,
			    __gnu_cxx::__ops::__negate(__pred),
			    std::__iterator_category(__first));
    }

/// Like find_if_not(), but uses and updates a count of the
  /// remaining range length instead of comparing against an end
  /// iterator.
  template<typename _InputIterator, typename _Predicate, typename _Distance>
    _InputIterator
    __find_if_not_n(_InputIterator __first, _Distance& __len, _Predicate __pred)
    {
      for (; __len; --__len,  (void) ++__first)
	if (!__pred(__first))
	  break;
      return __first;
    }

// set_difference
  // set_intersection
  // set_symmetric_difference
  // set_union
  // for_each
  // find
  // find_if
  // find_first_of
  // adjacent_find
  // count
  // count_if
  // search

template<typename _ForwardIterator1, typename _ForwardIterator2,
	   typename _BinaryPredicate>
    _ForwardIterator1
    __search(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
	     _ForwardIterator2 __first2, _ForwardIterator2 __last2,
	     _BinaryPredicate  __predicate)
    {
      // Test for empty ranges
      if (__first1 == __last1 || __first2 == __last2)
	return __first1;

// Test for a pattern of length 1.
      _ForwardIterator2 __p1(__first2);
      if (++__p1 == __last2)
	return std::__find_if(__first1, __last1,
		__gnu_cxx::__ops::__iter_comp_iter(__predicate, __first2));

// General case.
      _ForwardIterator2 __p;
      _ForwardIterator1 __current = __first1;

for (;;)
	{
	  __first1 =
	    std::__find_if(__first1, __last1,
		__gnu_cxx::__ops::__iter_comp_iter(__predicate, __first2));

if (__first1 == __last1)
	    return __last1;

__p = __p1;
	  __current = __first1;
	  if (++__current == __last1)
	    return __last1;

while (__predicate(__current, __p))
	    {
	      if (++__p == __last2)
		return __first1;
	      if (++__current == __last1)
		return __last1;
	    }
	  ++__first1;
	}
      return __first1;
    }

// search_n

/**
   *  This is an helper function for search_n overloaded for forward iterators.
  */
  template<typename _ForwardIterator, typename _Integer,
	   typename _UnaryPredicate>
    _ForwardIterator
    __search_n_aux(_ForwardIterator __first, _ForwardIterator __last,
		   _Integer __count, _UnaryPredicate __unary_pred,
		   std::forward_iterator_tag)
    {
      __first = std::__find_if(__first, __last, __unary_pred);
      while (__first != __last)
	{
	  typename iterator_traits<_ForwardIterator>::difference_type
	    __n = __count;
	  _ForwardIterator __i = __first;
	  ++__i;
	  while (__i != __last && __n != 1 && __unary_pred(__i))
	    {
	      ++__i;
	      --__n;
	    }
	  if (__n == 1)
	    return __first;
	  if (__i == __last)
	    return __last;
	  __first = std::__find_if(++__i, __last, __unary_pred);
	}
      return __last;
    }

/**
   *  This is an helper function for search_n overloaded for random access
   *  iterators.
  */
  template<typename _RandomAccessIter, typename _Integer,
	   typename _UnaryPredicate>
    _RandomAccessIter
    __search_n_aux(_RandomAccessIter __first, _RandomAccessIter __last,
		   _Integer __count, _UnaryPredicate __unary_pred,
		   std::random_access_iterator_tag)
    {
      typedef typename std::iterator_traits<_RandomAccessIter>::difference_type
	_DistanceType;

_DistanceType __tailSize = __last - __first;
      _DistanceType __remainder = __count;

while (__remainder <= __tailSize) // the main loop...
	{
	  __first += __remainder;
	  __tailSize -= __remainder;
	  // __first here is always pointing to one past the last element of
	  // next possible match.
	  _RandomAccessIter __backTrack = __first; 
	  while (__unary_pred(--__backTrack))
	    {
	      if (--__remainder == 0)
		return (__first - __count); // Success
	    }
	  __remainder = __count + 1 - (__first - __backTrack);
	}
      return __last; // Failure
    }

template<typename _ForwardIterator, typename _Integer,
	   typename _UnaryPredicate>
    _ForwardIterator
    __search_n(_ForwardIterator __first, _ForwardIterator __last,
	       _Integer __count,
	       _UnaryPredicate __unary_pred)
    {
      if (__count <= 0)
	return __first;

if (__count == 1)
	return std::__find_if(__first, __last, __unary_pred);

return std::__search_n_aux(__first, __last, __count, __unary_pred,
				 std::__iterator_category(__first));
    }

// find_end for forward iterators.
  template<typename _ForwardIterator1, typename _ForwardIterator2,
	   typename _BinaryPredicate>
    _ForwardIterator1
    __find_end(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
	       _ForwardIterator2 __first2, _ForwardIterator2 __last2,
	       forward_iterator_tag, forward_iterator_tag,
	       _BinaryPredicate __comp)
    {
      if (__first2 == __last2)
	return __last1;

_ForwardIterator1 __result = __last1;
      while (1)
	{
	  _ForwardIterator1 __new_result
	    = std::__search(__first1, __last1, __first2, __last2, __comp);
	  if (__new_result == __last1)
	    return __result;
	  else
	    {
	      __result = __new_result;
	      __first1 = __new_result;
	      ++__first1;
	    }
	}
    }

// find_end for bidirectional iterators (much faster).
  template<typename _BidirectionalIterator1, typename _BidirectionalIterator2,
	   typename _BinaryPredicate>
    _BidirectionalIterator1
    __find_end(_BidirectionalIterator1 __first1,
	       _BidirectionalIterator1 __last1,
	       _BidirectionalIterator2 __first2,
	       _BidirectionalIterator2 __last2,
	       bidirectional_iterator_tag, bidirectional_iterator_tag,
	       _BinaryPredicate __comp)
    {
      // concept requirements
      __glibcxx_function_requires(_BidirectionalIteratorConcept<
				  _BidirectionalIterator1>)
      __glibcxx_function_requires(_BidirectionalIteratorConcept<
				  _BidirectionalIterator2>)

typedef reverse_iterator<_BidirectionalIterator1> _RevIterator1;
      typedef reverse_iterator<_BidirectionalIterator2> _RevIterator2;

_RevIterator1 __rlast1(__first1);
      _RevIterator2 __rlast2(__first2);
      _RevIterator1 __rresult = std::__search(_RevIterator1(__last1), __rlast1,
					      _RevIterator2(__last2), __rlast2,
					      __comp);

if (__rresult == __rlast1)
	return __last1;
      else
	{
	  _BidirectionalIterator1 __result = __rresult.base();
	  std::advance(__result, -std::distance(__first2, __last2));
	  return __result;
	}
    }

/**
   *  @brief  Find last matching subsequence in a sequence.
   *  @ingroup non_mutating_algorithms
   *  @param  __first1  Start of range to search.
   *  @param  __last1   End of range to search.
   *  @param  __first2  Start of sequence to match.
   *  @param  __last2   End of sequence to match.
   *  @return   The last iterator @c i in the range
   *  @p [__first1,__last1-(__last2-__first2)) such that @c *(i+N) ==
   *  @p *(__first2+N) for each @c N in the range @p
   *  [0,__last2-__first2), or @p __last1 if no such iterator exists.
   *
   *  Searches the range @p [__first1,__last1) for a sub-sequence that
   *  compares equal value-by-value with the sequence given by @p
   *  [__first2,__last2) and returns an iterator to the __first
   *  element of the sub-sequence, or @p __last1 if the sub-sequence
   *  is not found.  The sub-sequence will be the last such
   *  subsequence contained in [__first1,__last1).
   *
   *  Because the sub-sequence must lie completely within the range @p
   *  [__first1,__last1) it must start at a position less than @p
   *  __last1-(__last2-__first2) where @p __last2-__first2 is the
   *  length of the sub-sequence.  This means that the returned
   *  iterator @c i will be in the range @p
   *  [__first1,__last1-(__last2-__first2))
  */
  template<typename _ForwardIterator1, typename _ForwardIterator2>
    inline _ForwardIterator1
    find_end(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
	     _ForwardIterator2 __first2, _ForwardIterator2 __last2)
    {
      // concept requirements
      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator1>)
      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator2>)
      __glibcxx_function_requires(_EqualOpConcept<
	    typename iterator_traits<_ForwardIterator1>::value_type,
	    typename iterator_traits<_ForwardIterator2>::value_type>)
      __glibcxx_requires_valid_range(__first1, __last1);
      __glibcxx_requires_valid_range(__first2, __last2);

return std::__find_end(__first1, __last1, __first2, __last2,
			     std::__iterator_category(__first1),
			     std::__iterator_category(__first2),
			     __gnu_cxx::__ops::__iter_equal_to_iter());
    }

/**
   *  @brief  Find last matching subsequence in a sequence using a predicate.
   *  @ingroup non_mutating_algorithms
   *  @param  __first1  Start of range to search.
   *  @param  __last1   End of range to search.
   *  @param  __first2  Start of sequence to match.
   *  @param  __last2   End of sequence to match.
   *  @param  __comp    The predicate to use.
   *  @return The last iterator @c i in the range @p
   *  [__first1,__last1-(__last2-__first2)) such that @c
   *  predicate(*(i+N), @p (__first2+N)) is true for each @c N in the
   *  range @p [0,__last2-__first2), or @p __last1 if no such iterator
   *  exists.
   *
   *  Searches the range @p [__first1,__last1) for a sub-sequence that
   *  compares equal value-by-value with the sequence given by @p
   *  [__first2,__last2) using comp as a predicate and returns an
   *  iterator to the first element of the sub-sequence, or @p __last1
   *  if the sub-sequence is not found.  The sub-sequence will be the
   *  last such subsequence contained in [__first,__last1).
   *
   *  Because the sub-sequence must lie completely within the range @p
   *  [__first1,__last1) it must start at a position less than @p
   *  __last1-(__last2-__first2) where @p __last2-__first2 is the
   *  length of the sub-sequence.  This means that the returned
   *  iterator @c i will be in the range @p
   *  [__first1,__last1-(__last2-__first2))
  */
  template<typename _ForwardIterator1, typename _ForwardIterator2,
	   typename _BinaryPredicate>
    inline _ForwardIterator1
    find_end(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
	     _ForwardIterator2 __first2, _ForwardIterator2 __last2,
	     _BinaryPredicate __comp)
    {
      // concept requirements
      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator1>)
      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator2>)
      __glibcxx_function_requires(_BinaryPredicateConcept<_BinaryPredicate,
	    typename iterator_traits<_ForwardIterator1>::value_type,
	    typename iterator_traits<_ForwardIterator2>::value_type>)
      __glibcxx_requires_valid_range(__first1, __last1);
      __glibcxx_requires_valid_range(__first2, __last2);

#if __cplusplus >= 201103L
  /**
   *  @brief  Checks that a predicate is true for all the elements
   *          of a sequence.
   *  @ingroup non_mutating_algorithms
   *  @param  __first   An input iterator.
   *  @param  __last    An input iterator.
   *  @param  __pred    A predicate.
   *  @return  True if the check is true, false otherwise.
   *
   *  Returns true if @p __pred is true for each element in the range
   *  @p [__first,__last), and false otherwise.
  */
  template<typename _InputIterator, typename _Predicate>
    inline bool
    all_of(_InputIterator __first, _InputIterator __last, _Predicate __pred)
    { return __last == std::find_if_not(__first, __last, __pred); }

/**
   *  @brief  Checks that a predicate is false for all the elements
   *          of a sequence.
   *  @ingroup non_mutating_algorithms
   *  @param  __first   An input iterator.
   *  @param  __last    An input iterator.
   *  @param  __pred    A predicate.
   *  @return  True if the check is true, false otherwise.
   *
   *  Returns true if @p __pred is false for each element in the range
   *  @p [__first,__last), and false otherwise.
  */
  template<typename _InputIterator, typename _Predicate>
    inline bool
    none_of(_InputIterator __first, _InputIterator __last, _Predicate __pred)
    { return __last == _GLIBCXX_STD_A::find_if(__first, __last, __pred); }

/**
   *  @brief  Checks that a predicate is false for at least an element
   *          of a sequence.
   *  @ingroup non_mutating_algorithms
   *  @param  __first   An input iterator.
   *  @param  __last    An input iterator.
   *  @param  __pred    A predicate.
   *  @return  True if the check is true, false otherwise.
   *
   *  Returns true if an element exists in the range @p
   *  [__first,__last) such that @p __pred is true, and false
   *  otherwise.
  */
  template<typename _InputIterator, typename _Predicate>
    inline bool
    any_of(_InputIterator __first, _InputIterator __last, _Predicate __pred)
    { return !std::none_of(__first, __last, __pred); }

/**
   *  @brief  Find the first element in a sequence for which a
   *          predicate is false.
   *  @ingroup non_mutating_algorithms
   *  @param  __first  An input iterator.
   *  @param  __last   An input iterator.
   *  @param  __pred   A predicate.
   *  @return   The first iterator @c i in the range @p [__first,__last)
   *  such that @p __pred(*i) is false, or @p __last if no such iterator exists.
  */
  template<typename _InputIterator, typename _Predicate>
    inline _InputIterator
    find_if_not(_InputIterator __first, _InputIterator __last,
		_Predicate __pred)
    {
      // concept requirements
      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
      __glibcxx_function_requires(_UnaryPredicateConcept<_Predicate,
	      typename iterator_traits<_InputIterator>::value_type>)
      __glibcxx_requires_valid_range(__first, __last);
      return std::__find_if_not(__first, __last,
				__gnu_cxx::__ops::__pred_iter(__pred));
    }

/**
   *  @brief  Checks whether the sequence is partitioned.
   *  @ingroup mutating_algorithms
   *  @param  __first  An input iterator.
   *  @param  __last   An input iterator.
   *  @param  __pred   A predicate.
   *  @return  True if the range @p [__first,__last) is partioned by @p __pred,
   *  i.e. if all elements that satisfy @p __pred appear before those that
   *  do not.
  */
  template<typename _InputIterator, typename _Predicate>
    inline bool
    is_partitioned(_InputIterator __first, _InputIterator __last,
		   _Predicate __pred)
    {
      __first = std::find_if_not(__first, __last, __pred);
      if (__first == __last)
	return true;
      ++__first;
      return std::none_of(__first, __last, __pred);
    }

/**
   *  @brief  Find the partition point of a partitioned range.
   *  @ingroup mutating_algorithms
   *  @param  __first   An iterator.
   *  @param  __last    Another iterator.
   *  @param  __pred    A predicate.
   *  @return  An iterator @p mid such that @p all_of(__first, mid, __pred)
   *           and @p none_of(mid, __last, __pred) are both true.
  */
  template<typename _ForwardIterator, typename _Predicate>
    _ForwardIterator
    partition_point(_ForwardIterator __first, _ForwardIterator __last,
		    _Predicate __pred)
    {
      // concept requirements
      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
      __glibcxx_function_requires(_UnaryPredicateConcept<_Predicate,
	      typename iterator_traits<_ForwardIterator>::value_type>)

// A specific debug-mode test will be necessary...
      __glibcxx_requires_valid_range(__first, __last);

typedef typename iterator_traits<_ForwardIterator>::difference_type
	_DistanceType;

_DistanceType __len = std::distance(__first, __last);
      _DistanceType __half;
      _ForwardIterator __middle;

while (__len > 0)
	{
	  __half = __len >> 1;
	  __middle = __first;
	  std::advance(__middle, __half);
	  if (__pred(*__middle))
	    {
	      __first = __middle;
	      ++__first;
	      __len = __len - __half - 1;
	    }
	  else
	    __len = __half;
	}
      return __first;
    }
#endif

template<typename _InputIterator, typename _OutputIterator,
	   typename _Predicate>
    _OutputIterator
    __remove_copy_if(_InputIterator __first, _InputIterator __last,
		     _OutputIterator __result, _Predicate __pred)
    {
      for (; __first != __last; ++__first)
	if (!__pred(__first))
	  {
	    *__result = *__first;
	    ++__result;
	  }
      return __result;
    }

/**
   *  @brief Copy a sequence, removing elements of a given value.
   *  @ingroup mutating_algorithms
   *  @param  __first   An input iterator.
   *  @param  __last    An input iterator.
   *  @param  __result  An output iterator.
   *  @param  __value   The value to be removed.
   *  @return   An iterator designating the end of the resulting sequence.
   *
   *  Copies each element in the range @p [__first,__last) not equal
   *  to @p __value to the range beginning at @p __result.
   *  remove_copy() is stable, so the relative order of elements that
   *  are copied is unchanged.
  */
  template<typename _InputIterator, typename _OutputIterator, typename _Tp>
    inline _OutputIterator
    remove_copy(_InputIterator __first, _InputIterator __last,
		_OutputIterator __result, const _Tp& __value)
    {
      // concept requirements
      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
	    typename iterator_traits<_InputIterator>::value_type>)
      __glibcxx_function_requires(_EqualOpConcept<
	    typename iterator_traits<_InputIterator>::value_type, _Tp>)
      __glibcxx_requires_valid_range(__first, __last);

return std::__remove_copy_if(__first, __last, __result,
	__gnu_cxx::__ops::__iter_equals_val(__value));
    }

/**
   *  @brief Copy a sequence, removing elements for which a predicate is true.
   *  @ingroup mutating_algorithms
   *  @param  __first   An input iterator.
   *  @param  __last    An input iterator.
   *  @param  __result  An output iterator.
   *  @param  __pred    A predicate.
   *  @return   An iterator designating the end of the resulting sequence.
   *
   *  Copies each element in the range @p [__first,__last) for which
   *  @p __pred returns false to the range beginning at @p __result.
   *
   *  remove_copy_if() is stable, so the relative order of elements that are
   *  copied is unchanged.
  */
  template<typename _InputIterator, typename _OutputIterator,
	   typename _Predicate>
    inline _OutputIterator
    remove_copy_if(_InputIterator __first, _InputIterator __last,
		   _OutputIterator __result, _Predicate __pred)
    {
      // concept requirements
      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
	    typename iterator_traits<_InputIterator>::value_type>)
      __glibcxx_function_requires(_UnaryPredicateConcept<_Predicate,
	    typename iterator_traits<_InputIterator>::value_type>)
      __glibcxx_requires_valid_range(__first, __last);

return std::__remove_copy_if(__first, __last, __result,
				   __gnu_cxx::__ops::__pred_iter(__pred));
    }

#if __cplusplus >= 201103L
  /**
   *  @brief Copy the elements of a sequence for which a predicate is true.
   *  @ingroup mutating_algorithms
   *  @param  __first   An input iterator.
   *  @param  __last    An input iterator.
   *  @param  __result  An output iterator.
   *  @param  __pred    A predicate.
   *  @return   An iterator designating the end of the resulting sequence.
   *
   *  Copies each element in the range @p [__first,__last) for which
   *  @p __pred returns true to the range beginning at @p __result.
   *
   *  copy_if() is stable, so the relative order of elements that are
   *  copied is unchanged.
  */
  template<typename _InputIterator, typename _OutputIterator,
	   typename _Predicate>
    _OutputIterator
    copy_if(_InputIterator __first, _InputIterator __last,
	    _OutputIterator __result, _Predicate __pred)
    {
      // concept requirements
      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
	    typename iterator_traits<_InputIterator>::value_type>)
      __glibcxx_function_requires(_UnaryPredicateConcept<_Predicate,
	    typename iterator_traits<_InputIterator>::value_type>)
      __glibcxx_requires_valid_range(__first, __last);

for (; __first != __last; ++__first)
	if (__pred(*__first))
	  {
	    *__result = *__first;
	    ++__result;
	  }
      return __result;
    }

template<typename _InputIterator, typename _Size, typename _OutputIterator>
    _OutputIterator
    __copy_n(_InputIterator __first, _Size __n,
	     _OutputIterator __result, input_iterator_tag)
    {
      if (__n > 0)
	{
	  while (true)
	    {
	      *__result = *__first;
	      ++__result;
	      if (--__n > 0)
		++__first;
	      else
		break;
	    }
	}
      return __result;
    }

template<typename _RandomAccessIterator, typename _Size,
	   typename _OutputIterator>
    inline _OutputIterator
    __copy_n(_RandomAccessIterator __first, _Size __n,
	     _OutputIterator __result, random_access_iterator_tag)
    { return std::copy(__first, __first + __n, __result); }

/**
   *  @brief Copies the range [first,first+n) into [result,result+n).
   *  @ingroup mutating_algorithms
   *  @param  __first  An input iterator.
   *  @param  __n      The number of elements to copy.
   *  @param  __result An output iterator.
   *  @return  result+n.
   *
   *  This inline function will boil down to a call to @c memmove whenever
   *  possible.  Failing that, if random access iterators are passed, then the
   *  loop count will be known (and therefore a candidate for compiler
   *  optimizations such as unrolling).
  */
  template<typename _InputIterator, typename _Size, typename _OutputIterator>
    inline _OutputIterator
    copy_n(_InputIterator __first, _Size __n, _OutputIterator __result)
    {
      // concept requirements
      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
	    typename iterator_traits<_InputIterator>::value_type>)

return std::__copy_n(__first, __n, __result,
			   std::__iterator_category(__first));
    }

/**
   *  @brief Copy the elements of a sequence to separate output sequences
   *         depending on the truth value of a predicate.
   *  @ingroup mutating_algorithms
   *  @param  __first   An input iterator.
   *  @param  __last    An input iterator.
   *  @param  __out_true   An output iterator.
   *  @param  __out_false  An output iterator.
   *  @param  __pred    A predicate.
   *  @return   A pair designating the ends of the resulting sequences.
   *
   *  Copies each element in the range @p [__first,__last) for which
   *  @p __pred returns true to the range beginning at @p out_true
   *  and each element for which @p __pred returns false to @p __out_false.
  */
  template<typename _InputIterator, typename _OutputIterator1,
	   typename _OutputIterator2, typename _Predicate>
    pair<_OutputIterator1, _OutputIterator2>
    partition_copy(_InputIterator __first, _InputIterator __last,
		   _OutputIterator1 __out_true, _OutputIterator2 __out_false,
		   _Predicate __pred)
    {
      // concept requirements
      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator1,
	    typename iterator_traits<_InputIterator>::value_type>)
      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator2,
	    typename iterator_traits<_InputIterator>::value_type>)
      __glibcxx_function_requires(_UnaryPredicateConcept<_Predicate,
	    typename iterator_traits<_InputIterator>::value_type>)
      __glibcxx_requires_valid_range(__first, __last);
      
      for (; __first != __last; ++__first)
	if (__pred(*__first))
	  {
	    *__out_true = *__first;
	    ++__out_true;
	  }
	else
	  {
	    *__out_false = *__first;
	    ++__out_false;
	  }

return pair<_OutputIterator1, _OutputIterator2>(__out_true, __out_false);
    }
#endif

template<typename _ForwardIterator, typename _Predicate>
    _ForwardIterator
    __remove_if(_ForwardIterator __first, _ForwardIterator __last,
		_Predicate __pred)
    {
      __first = std::__find_if(__first, __last, __pred);
      if (__first == __last)
	return __first;
      _ForwardIterator __result = __first;
      ++__first;
      for (; __first != __last; ++__first)
	if (!__pred(__first))
	  {
	    *__result = _GLIBCXX_MOVE(*__first);
	    ++__result;
	  }
      return __result;
    }

/**
   *  @brief Remove elements from a sequence.
   *  @ingroup mutating_algorithms
   *  @param  __first  An input iterator.
   *  @param  __last   An input iterator.
   *  @param  __value  The value to be removed.
   *  @return   An iterator designating the end of the resulting sequence.
   *
   *  All elements equal to @p __value are removed from the range
   *  @p [__first,__last).
   *
   *  remove() is stable, so the relative order of elements that are
   *  not removed is unchanged.
   *
   *  Elements between the end of the resulting sequence and @p __last
   *  are still present, but their value is unspecified.
  */
  template<typename _ForwardIterator, typename _Tp>
    inline _ForwardIterator
    remove(_ForwardIterator __first, _ForwardIterator __last,
	   const _Tp& __value)
    {
      // concept requirements
      __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
				  _ForwardIterator>)
      __glibcxx_function_requires(_EqualOpConcept<
	    typename iterator_traits<_ForwardIterator>::value_type, _Tp>)
      __glibcxx_requires_valid_range(__first, __last);

return std::__remove_if(__first, __last,
		__gnu_cxx::__ops::__iter_equals_val(__value));
    }

/**
   *  @brief Remove elements from a sequence using a predicate.
   *  @ingroup mutating_algorithms
   *  @param  __first  A forward iterator.
   *  @param  __last   A forward iterator.
   *  @param  __pred   A predicate.
   *  @return   An iterator designating the end of the resulting sequence.
   *
   *  All elements for which @p __pred returns true are removed from the range
   *  @p [__first,__last).
   *
   *  remove_if() is stable, so the relative order of elements that are
   *  not removed is unchanged.
   *
   *  Elements between the end of the resulting sequence and @p __last
   *  are still present, but their value is unspecified.
  */
  template<typename _ForwardIterator, typename _Predicate>
    inline _ForwardIterator
    remove_if(_ForwardIterator __first, _ForwardIterator __last,
	      _Predicate __pred)
    {
      // concept requirements
      __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
				  _ForwardIterator>)
      __glibcxx_function_requires(_UnaryPredicateConcept<_Predicate,
	    typename iterator_traits<_ForwardIterator>::value_type>)
      __glibcxx_requires_valid_range(__first, __last);

return std::__remove_if(__first, __last,
			      __gnu_cxx::__ops::__pred_iter(__pred));
    }

template<typename _ForwardIterator, typename _BinaryPredicate>
    _ForwardIterator
    __adjacent_find(_ForwardIterator __first, _ForwardIterator __last,
		    _BinaryPredicate __binary_pred)
    {
      if (__first == __last)
	return __last;
      _ForwardIterator __next = __first;
      while (++__next != __last)
	{
	  if (__binary_pred(__first, __next))
	    return __first;
	  __first = __next;
	}
      return __last;
    }

template<typename _ForwardIterator, typename _BinaryPredicate>
    _ForwardIterator
    __unique(_ForwardIterator __first, _ForwardIterator __last,
	     _BinaryPredicate __binary_pred)
    {
      // Skip the beginning, if already unique.
      __first = std::__adjacent_find(__first, __last, __binary_pred);
      if (__first == __last)
	return __last;

// Do the real copy work.
      _ForwardIterator __dest = __first;
      ++__first;
      while (++__first != __last)
	if (!__binary_pred(__dest, __first))
	  *++__dest = _GLIBCXX_MOVE(*__first);
      return ++__dest;
    }

/**
   *  @brief Remove consecutive duplicate values from a sequence.
   *  @ingroup mutating_algorithms
   *  @param  __first  A forward iterator.
   *  @param  __last   A forward iterator.
   *  @return  An iterator designating the end of the resulting sequence.
   *
   *  Removes all but the first element from each group of consecutive
   *  values that compare equal.
   *  unique() is stable, so the relative order of elements that are
   *  not removed is unchanged.
   *  Elements between the end of the resulting sequence and @p __last
   *  are still present, but their value is unspecified.
  */
  template<typename _ForwardIterator>
    inline _ForwardIterator
    unique(_ForwardIterator __first, _ForwardIterator __last)
    {
      // concept requirements
      __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
				  _ForwardIterator>)
      __glibcxx_function_requires(_EqualityComparableConcept<
		     typename iterator_traits<_ForwardIterator>::value_type>)
      __glibcxx_requires_valid_range(__first, __last);

return std::__unique(__first, __last,
			   __gnu_cxx::__ops::__iter_equal_to_iter());
    }

/**
   *  @brief Remove consecutive values from a sequence using a predicate.
   *  @ingroup mutating_algorithms
   *  @param  __first        A forward iterator.
   *  @param  __last         A forward iterator.
   *  @param  __binary_pred  A binary predicate.
   *  @return  An iterator designating the end of the resulting sequence.
   *
   *  Removes all but the first element from each group of consecutive
   *  values for which @p __binary_pred returns true.
   *  unique() is stable, so the relative order of elements that are
   *  not removed is unchanged.
   *  Elements between the end of the resulting sequence and @p __last
   *  are still present, but their value is unspecified.
  */
  template<typename _ForwardIterator, typename _BinaryPredicate>
    inline _ForwardIterator
    unique(_ForwardIterator __first, _ForwardIterator __last,
	   _BinaryPredicate __binary_pred)
    {
      // concept requirements
      __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
				  _ForwardIterator>)
      __glibcxx_function_requires(_BinaryPredicateConcept<_BinaryPredicate,
		typename iterator_traits<_ForwardIterator>::value_type,
		typename iterator_traits<_ForwardIterator>::value_type>)
      __glibcxx_requires_valid_range(__first, __last);

return std::__unique(__first, __last,
			   __gnu_cxx::__ops::__iter_comp_iter(__binary_pred));
    }

/**
   *  This is an uglified
   *  unique_copy(_InputIterator, _InputIterator, _OutputIterator,
   *              _BinaryPredicate)
   *  overloaded for forward iterators and output iterator as result.
  */
  template<typename _ForwardIterator, typename _OutputIterator,
	   typename _BinaryPredicate>
    _OutputIterator
    __unique_copy(_ForwardIterator __first, _ForwardIterator __last,
		  _OutputIterator __result, _BinaryPredicate __binary_pred,
		  forward_iterator_tag, output_iterator_tag)
    {
      // concept requirements -- iterators already checked
      __glibcxx_function_requires(_BinaryPredicateConcept<_BinaryPredicate,
	  typename iterator_traits<_ForwardIterator>::value_type,
	  typename iterator_traits<_ForwardIterator>::value_type>)

_ForwardIterator __next = __first;
      *__result = *__first;
      while (++__next != __last)
	if (!__binary_pred(__first, __next))
	  {
	    __first = __next;
	    *++__result = *__first;
	  }
      return ++__result;
    }

/**
   *  This is an uglified
   *  unique_copy(_InputIterator, _InputIterator, _OutputIterator,
   *              _BinaryPredicate)
   *  overloaded for input iterators and output iterator as result.
  */
  template<typename _InputIterator, typename _OutputIterator,
	   typename _BinaryPredicate>
    _OutputIterator
    __unique_copy(_InputIterator __first, _InputIterator __last,
		  _OutputIterator __result, _BinaryPredicate __binary_pred,
		  input_iterator_tag, output_iterator_tag)
    {
      // concept requirements -- iterators already checked
      __glibcxx_function_requires(_BinaryPredicateConcept<_BinaryPredicate,
	  typename iterator_traits<_InputIterator>::value_type,
	  typename iterator_traits<_InputIterator>::value_type>)

typename iterator_traits<_InputIterator>::value_type __value = *__first;
      __decltype(__gnu_cxx::__ops::__iter_comp_val(__binary_pred))
	__rebound_pred
	= __gnu_cxx::__ops::__iter_comp_val(__binary_pred);
      *__result = __value;
      while (++__first != __last)
	if (!__rebound_pred(__first, __value))
	  {
	    __value = *__first;
	    *++__result = __value;
	  }
      return ++__result;
    }

/**
   *  This is an uglified
   *  unique_copy(_InputIterator, _InputIterator, _OutputIterator,
   *              _BinaryPredicate)
   *  overloaded for input iterators and forward iterator as result.
  */
  template<typename _InputIterator, typename _ForwardIterator,
	   typename _BinaryPredicate>
    _ForwardIterator
    __unique_copy(_InputIterator __first, _InputIterator __last,
		  _ForwardIterator __result, _BinaryPredicate __binary_pred,
		  input_iterator_tag, forward_iterator_tag)
    {
      // concept requirements -- iterators already checked
      __glibcxx_function_requires(_BinaryPredicateConcept<_BinaryPredicate,
	  typename iterator_traits<_ForwardIterator>::value_type,
	  typename iterator_traits<_InputIterator>::value_type>)
      *__result = *__first;
      while (++__first != __last)
	if (!__binary_pred(__result, __first))
	  *++__result = *__first;
      return ++__result;
    }

/**
   *  This is an uglified reverse(_BidirectionalIterator,
   *                              _BidirectionalIterator)
   *  overloaded for bidirectional iterators.
  */
  template<typename _BidirectionalIterator>
    void
    __reverse(_BidirectionalIterator __first, _BidirectionalIterator __last,
	      bidirectional_iterator_tag)
    {
      while (true)
	if (__first == __last || __first == --__last)
	  return;
	else
	  {
	    std::iter_swap(__first, __last);
	    ++__first;
	  }
    }

/**
   *  This is an uglified reverse(_BidirectionalIterator,
   *                              _BidirectionalIterator)
   *  overloaded for random access iterators.
  */
  template<typename _RandomAccessIterator>
    void
    __reverse(_RandomAccessIterator __first, _RandomAccessIterator __last,
	      random_access_iterator_tag)
    {
      if (__first == __last)
	return;
      --__last;
      while (__first < __last)
	{
	  std::iter_swap(__first, __last);
	  ++__first;
	  --__last;
	}
    }

/**
   *  @brief Reverse a sequence.
   *  @ingroup mutating_algorithms
   *  @param  __first  A bidirectional iterator.
   *  @param  __last   A bidirectional iterator.
   *  @return   reverse() returns no value.
   *
   *  Reverses the order of the elements in the range @p [__first,__last),
   *  so that the first element becomes the last etc.
   *  For every @c i such that @p 0<=i<=(__last-__first)/2), @p reverse()
   *  swaps @p *(__first+i) and @p *(__last-(i+1))
  */
  template<typename _BidirectionalIterator>
    inline void
    reverse(_BidirectionalIterator __first, _BidirectionalIterator __last)
    {
      // concept requirements
      __glibcxx_function_requires(_Mutable_BidirectionalIteratorConcept<
				  _BidirectionalIterator>)
      __glibcxx_requires_valid_range(__first, __last);
      std::__reverse(__first, __last, std::__iterator_category(__first));
    }

/**
   *  @brief Copy a sequence, reversing its elements.
   *  @ingroup mutating_algorithms
   *  @param  __first   A bidirectional iterator.
   *  @param  __last    A bidirectional iterator.
   *  @param  __result  An output iterator.
   *  @return  An iterator designating the end of the resulting sequence.
   *
   *  Copies the elements in the range @p [__first,__last) to the
   *  range @p [__result,__result+(__last-__first)) such that the
   *  order of the elements is reversed.  For every @c i such that @p
   *  0<=i<=(__last-__first), @p reverse_copy() performs the
   *  assignment @p *(__result+(__last-__first)-1-i) = *(__first+i).
   *  The ranges @p [__first,__last) and @p
   *  [__result,__result+(__last-__first)) must not overlap.
  */
  template<typename _BidirectionalIterator, typename _OutputIterator>
    _OutputIterator
    reverse_copy(_BidirectionalIterator __first, _BidirectionalIterator __last,
		 _OutputIterator __result)
    {
      // concept requirements
      __glibcxx_function_requires(_BidirectionalIteratorConcept<
				  _BidirectionalIterator>)
      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
		typename iterator_traits<_BidirectionalIterator>::value_type>)
      __glibcxx_requires_valid_range(__first, __last);

while (__first != __last)
	{
	  --__last;
	  *__result = *__last;
	  ++__result;
	}
      return __result;
    }

/**
   *  This is a helper function for the rotate algorithm specialized on RAIs.
   *  It returns the greatest common divisor of two integer values.
  */
  template<typename _EuclideanRingElement>
    _EuclideanRingElement
    __gcd(_EuclideanRingElement __m, _EuclideanRingElement __n)
    {
      while (__n != 0)
	{
	  _EuclideanRingElement __t = __m % __n;
	  __m = __n;
	  __n = __t;
	}
      return __m;
    }

inline namespace _V2
  {

/// This is a helper function for the rotate algorithm.
  template<typename _ForwardIterator>
    _ForwardIterator
    __rotate(_ForwardIterator __first,
	     _ForwardIterator __middle,
	     _ForwardIterator __last,
	     forward_iterator_tag)
    {
      if (__first == __middle)
	return __last;
      else if (__last  == __middle)
	return __first;

_ForwardIterator __first2 = __middle;
      do
	{
	  std::iter_swap(__first, __first2);
	  ++__first;
	  ++__first2;
	  if (__first == __middle)
	    __middle = __first2;
	}
      while (__first2 != __last);

_ForwardIterator __ret = __first;

__first2 = __middle;

while (__first2 != __last)
	{
	  std::iter_swap(__first, __first2);
	  ++__first;
	  ++__first2;
	  if (__first == __middle)
	    __middle = __first2;
	  else if (__first2 == __last)
	    __first2 = __middle;
	}
      return __ret;
    }

/// This is a helper function for the rotate algorithm.
  template<typename _BidirectionalIterator>
    _BidirectionalIterator
    __rotate(_BidirectionalIterator __first,
	     _BidirectionalIterator __middle,
	     _BidirectionalIterator __last,
	      bidirectional_iterator_tag)
    {
      // concept requirements
      __glibcxx_function_requires(_Mutable_BidirectionalIteratorConcept<
				  _BidirectionalIterator>)

if (__first == __middle)
	return __last;
      else if (__last  == __middle)
	return __first;

std::__reverse(__first,  __middle, bidirectional_iterator_tag());
      std::__reverse(__middle, __last,   bidirectional_iterator_tag());

while (__first != __middle && __middle != __last)
	{
	  std::iter_swap(__first, --__last);
	  ++__first;
	}

if (__first == __middle)
	{
	  std::__reverse(__middle, __last,   bidirectional_iterator_tag());
	  return __last;
	}
      else
	{
	  std::__reverse(__first,  __middle, bidirectional_iterator_tag());
	  return __first;
	}
    }

/// This is a helper function for the rotate algorithm.
  template<typename _RandomAccessIterator>
    _RandomAccessIterator
    __rotate(_RandomAccessIterator __first,
	     _RandomAccessIterator __middle,
	     _RandomAccessIterator __last,
	     random_access_iterator_tag)
    {
      // concept requirements
      __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
				  _RandomAccessIterator>)

if (__first == __middle)
	return __last;
      else if (__last  == __middle)
	return __first;

typedef typename iterator_traits<_RandomAccessIterator>::difference_type
	_Distance;
      typedef typename iterator_traits<_RandomAccessIterator>::value_type
	_ValueType;

_Distance __n = __last   - __first;
      _Distance __k = __middle - __first;

if (__k == __n - __k)
	{
	  std::swap_ranges(__first, __middle, __middle);
	  return __middle;
	}

_RandomAccessIterator __p = __first;
      _RandomAccessIterator __ret = __first + (__last - __middle);

for (;;)
	{
	  if (__k < __n - __k)
	    {
	      if (__is_pod(_ValueType) && __k == 1)
		{
		  _ValueType __t = _GLIBCXX_MOVE(*__p);
		  _GLIBCXX_MOVE3(__p + 1, __p + __n, __p);
		  *(__p + __n - 1) = _GLIBCXX_MOVE(__t);
		  return __ret;
		}
	      _RandomAccessIterator __q = __p + __k;
	      for (_Distance __i = 0; __i < __n - __k; ++ __i)
		{
		  std::iter_swap(__p, __q);
		  ++__p;
		  ++__q;
		}
	      __n %= __k;
	      if (__n == 0)
		return __ret;
	      std::swap(__n, __k);
	      __k = __n - __k;
	    }
	  else
	    {
	      __k = __n - __k;
	      if (__is_pod(_ValueType) && __k == 1)
		{
		  _ValueType __t = _GLIBCXX_MOVE(*(__p + __n - 1));
		  _GLIBCXX_MOVE_BACKWARD3(__p, __p + __n - 1, __p + __n);
		  *__p = _GLIBCXX_MOVE(__t);
		  return __ret;
		}
	      _RandomAccessIterator __q = __p + __n;
	      __p = __q - __k;
	      for (_Distance __i = 0; __i < __n - __k; ++ __i)
		{
		  --__p;
		  --__q;
		  std::iter_swap(__p, __q);
		}
	      __n %= __k;
	      if (__n == 0)
		return __ret;
	      std::swap(__n, __k);
	    }
	}
    }

// _GLIBCXX_RESOLVE_LIB_DEFECTS
   // DR 488. rotate throws away useful information
  /**
   *  @brief Rotate the elements of a sequence.
   *  @ingroup mutating_algorithms
   *  @param  __first   A forward iterator.
   *  @param  __middle  A forward iterator.
   *  @param  __last    A forward iterator.
   *  @return  first + (last - middle).
   *
   *  Rotates the elements of the range @p [__first,__last) by 
   *  @p (__middle - __first) positions so that the element at @p __middle
   *  is moved to @p __first, the element at @p __middle+1 is moved to
   *  @p __first+1 and so on for each element in the range
   *  @p [__first,__last).
   *
   *  This effectively swaps the ranges @p [__first,__middle) and
   *  @p [__middle,__last).
   *
   *  Performs
   *   @p *(__first+(n+(__last-__middle))%(__last-__first))=*(__first+n)
   *  for each @p n in the range @p [0,__last-__first).
  */
  template<typename _ForwardIterator>
    inline _ForwardIterator
    rotate(_ForwardIterator __first, _ForwardIterator __middle,
	   _ForwardIterator __last)
    {
      // concept requirements
      __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
				  _ForwardIterator>)
      __glibcxx_requires_valid_range(__first, __middle);
      __glibcxx_requires_valid_range(__middle, __last);

return std::__rotate(__first, __middle, __last,
			   std::__iterator_category(__first));
    }

} // namespace _V2

/**
   *  @brief Copy a sequence, rotating its elements.
   *  @ingroup mutating_algorithms
   *  @param  __first   A forward iterator.
   *  @param  __middle  A forward iterator.
   *  @param  __last    A forward iterator.
   *  @param  __result  An output iterator.
   *  @return   An iterator designating the end of the resulting sequence.
   *
   *  Copies the elements of the range @p [__first,__last) to the
   *  range beginning at @result, rotating the copied elements by 
   *  @p (__middle-__first) positions so that the element at @p __middle
   *  is moved to @p __result, the element at @p __middle+1 is moved
   *  to @p __result+1 and so on for each element in the range @p
   *  [__first,__last).
   *
   *  Performs 
   *  @p *(__result+(n+(__last-__middle))%(__last-__first))=*(__first+n)
   *  for each @p n in the range @p [0,__last-__first).
  */
  template<typename _ForwardIterator, typename _OutputIterator>
    inline _OutputIterator
    rotate_copy(_ForwardIterator __first, _ForwardIterator __middle,
		_ForwardIterator __last, _OutputIterator __result)
    {
      // concept requirements
      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
		typename iterator_traits<_ForwardIterator>::value_type>)
      __glibcxx_requires_valid_range(__first, __middle);
      __glibcxx_requires_valid_range(__middle, __last);

return std::copy(__first, __middle,
		       std::copy(__middle, __last, __result));
    }

/// This is a helper function...
  template<typename _ForwardIterator, typename _Predicate>
    _ForwardIterator
    __partition(_ForwardIterator __first, _ForwardIterator __last,
		_Predicate __pred, forward_iterator_tag)
    {
      if (__first == __last)
	return __first;

while (__pred(*__first))
	if (++__first == __last)
	  return __first;

_ForwardIterator __next = __first;

while (++__next != __last)
	if (__pred(*__next))
	  {
	    std::iter_swap(__first, __next);
	    ++__first;
	  }

return __first;
    }

/// This is a helper function...
  template<typename _BidirectionalIterator, typename _Predicate>
    _BidirectionalIterator
    __partition(_BidirectionalIterator __first, _BidirectionalIterator __last,
		_Predicate __pred, bidirectional_iterator_tag)
    {
      while (true)
	{
	  while (true)
	    if (__first == __last)
	      return __first;
	    else if (__pred(*__first))
	      ++__first;
	    else
	      break;
	  --__last;
	  while (true)
	    if (__first == __last)
	      return __first;
	    else if (!bool(__pred(*__last)))
	      --__last;
	    else
	      break;
	  std::iter_swap(__first, __last);
	  ++__first;
	}
    }

// partition

/// This is a helper function...
  /// Requires __first != __last and !__pred(__first)
  /// and __len == distance(__first, __last).
  ///
  /// !__pred(__first) allows us to guarantee that we don't
  /// move-assign an element onto itself.
  template<typename _ForwardIterator, typename _Pointer, typename _Predicate,
	   typename _Distance>
    _ForwardIterator
    __stable_partition_adaptive(_ForwardIterator __first,
				_ForwardIterator __last,
				_Predicate __pred, _Distance __len,
				_Pointer __buffer,
				_Distance __buffer_size)
    {
      if (__len == 1)
	return __first;

if (__len <= __buffer_size)
	{
	  _ForwardIterator __result1 = __first;
	  _Pointer __result2 = __buffer;

// The precondition guarantees that !__pred(__first), so
	  // move that element to the buffer before starting the loop.
	  // This ensures that we only call __pred once per element.
	  *__result2 = _GLIBCXX_MOVE(*__first);
	  ++__result2;
	  ++__first;
	  for (; __first != __last; ++__first)
	    if (__pred(__first))
	      {
		*__result1 = _GLIBCXX_MOVE(*__first);
		++__result1;
	      }
	    else
	      {
		*__result2 = _GLIBCXX_MOVE(*__first);
		++__result2;
	      }

_GLIBCXX_MOVE3(__buffer, __result2, __result1);
	  return __result1;
	}

_ForwardIterator __middle = __first;
      std::advance(__middle, __len / 2);
      _ForwardIterator __left_split =
	std::__stable_partition_adaptive(__first, __middle, __pred,
					 __len / 2, __buffer,
					 __buffer_size);

// Advance past true-predicate values to satisfy this
      // function's preconditions.
      _Distance __right_len = __len - __len / 2;
      _ForwardIterator __right_split =
	std::__find_if_not_n(__middle, __right_len, __pred);

if (__right_len)
	__right_split =
	  std::__stable_partition_adaptive(__right_split, __last, __pred,
					   __right_len,
					   __buffer, __buffer_size);

std::rotate(__left_split, __middle, __right_split);
      std::advance(__left_split, std::distance(__middle, __right_split));
      return __left_split;
    }

template<typename _ForwardIterator, typename _Predicate>
    _ForwardIterator
    __stable_partition(_ForwardIterator __first, _ForwardIterator __last,
		       _Predicate __pred)
    {
      __first = std::__find_if_not(__first, __last, __pred);

if (__first == __last)
	return __first;

typedef typename iterator_traits<_ForwardIterator>::value_type
	_ValueType;
      typedef typename iterator_traits<_ForwardIterator>::difference_type
	_DistanceType;

_Temporary_buffer<_ForwardIterator, _ValueType> __buf(__first, __last);
      return
	std::__stable_partition_adaptive(__first, __last, __pred,
					 _DistanceType(__buf.requested_size()),
					 __buf.begin(),
					 _DistanceType(__buf.size()));
    }

/**
   *  @brief Move elements for which a predicate is true to the beginning
   *         of a sequence, preserving relative ordering.
   *  @ingroup mutating_algorithms
   *  @param  __first   A forward iterator.
   *  @param  __last    A forward iterator.
   *  @param  __pred    A predicate functor.
   *  @return  An iterator @p middle such that @p __pred(i) is true for each
   *  iterator @p i in the range @p [first,middle) and false for each @p i
   *  in the range @p [middle,last).
   *
   *  Performs the same function as @p partition() with the additional
   *  guarantee that the relative ordering of elements in each group is
   *  preserved, so any two elements @p x and @p y in the range
   *  @p [__first,__last) such that @p __pred(x)==__pred(y) will have the same
   *  relative ordering after calling @p stable_partition().
  */
  template<typename _ForwardIterator, typename _Predicate>
    inline _ForwardIterator
    stable_partition(_ForwardIterator __first, _ForwardIterator __last,
		     _Predicate __pred)
    {
      // concept requirements
      __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
				  _ForwardIterator>)
      __glibcxx_function_requires(_UnaryPredicateConcept<_Predicate,
	    typename iterator_traits<_ForwardIterator>::value_type>)
      __glibcxx_requires_valid_range(__first, __last);

return std::__stable_partition(__first, __last,
				     __gnu_cxx::__ops::__pred_iter(__pred));
    }

/// This is a helper function for the sort routines.
  template<typename _RandomAccessIterator, typename _Compare>
    void
    __heap_select(_RandomAccessIterator __first,
		  _RandomAccessIterator __middle,
		  _RandomAccessIterator __last, _Compare __comp)
    {
      std::__make_heap(__first, __middle, __comp);
      for (_RandomAccessIterator __i = __middle; __i < __last; ++__i)
	if (__comp(__i, __first))
	  std::__pop_heap(__first, __middle, __i, __comp);
    }

// partial_sort

template<typename _InputIterator, typename _RandomAccessIterator,
	   typename _Compare>
    _RandomAccessIterator
    __partial_sort_copy(_InputIterator __first, _InputIterator __last,
			_RandomAccessIterator __result_first,
			_RandomAccessIterator __result_last,
			_Compare __comp)
    {
      typedef typename iterator_traits<_InputIterator>::value_type
	_InputValueType;
      typedef iterator_traits<_RandomAccessIterator> _RItTraits;
      typedef typename _RItTraits::difference_type _DistanceType;

if (__result_first == __result_last)
	return __result_last;
      _RandomAccessIterator __result_real_last = __result_first;
      while (__first != __last && __result_real_last != __result_last)
	{
	  *__result_real_last = *__first;
	  ++__result_real_last;
	  ++__first;
	}
      
      std::__make_heap(__result_first, __result_real_last, __comp);
      while (__first != __last)
	{
	  if (__comp(__first, __result_first))
	    std::__adjust_heap(__result_first, _DistanceType(0),
			       _DistanceType(__result_real_last
					     - __result_first),
			       _InputValueType(*__first), __comp);
	  ++__first;
	}
      std::__sort_heap(__result_first, __result_real_last, __comp);
      return __result_real_last;
    }

/**
   *  @brief Copy the smallest elements of a sequence.
   *  @ingroup sorting_algorithms
   *  @param  __first   An iterator.
   *  @param  __last    Another iterator.
   *  @param  __result_first   A random-access iterator.
   *  @param  __result_last    Another random-access iterator.
   *  @return   An iterator indicating the end of the resulting sequence.
   *
   *  Copies and sorts the smallest N values from the range @p [__first,__last)
   *  to the range beginning at @p __result_first, where the number of
   *  elements to be copied, @p N, is the smaller of @p (__last-__first) and
   *  @p (__result_last-__result_first).
   *  After the sort if @e i and @e j are iterators in the range
   *  @p [__result_first,__result_first+N) such that i precedes j then
   *  *j<*i is false.
   *  The value returned is @p __result_first+N.
  */
  template<typename _InputIterator, typename _RandomAccessIterator>
    inline _RandomAccessIterator
    partial_sort_copy(_InputIterator __first, _InputIterator __last,
		      _RandomAccessIterator __result_first,
		      _RandomAccessIterator __result_last)
    {
#ifdef _GLIBCXX_CONCEPT_CHECKS
      typedef typename iterator_traits<_InputIterator>::value_type
	_InputValueType;
      typedef typename iterator_traits<_RandomAccessIterator>::value_type
	_OutputValueType;
#endif

// concept requirements
      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
      __glibcxx_function_requires(_ConvertibleConcept<_InputValueType,
				  _OutputValueType>)
      __glibcxx_function_requires(_LessThanOpConcept<_InputValueType,
						     _OutputValueType>)
      __glibcxx_function_requires(_LessThanComparableConcept<_OutputValueType>)
      __glibcxx_requires_valid_range(__first, __last);
      __glibcxx_requires_irreflexive(__first, __last);
      __glibcxx_requires_valid_range(__result_first, __result_last);

return std::__partial_sort_copy(__first, __last,
				      __result_first, __result_last,
				      __gnu_cxx::__ops::__iter_less_iter());
    }

/**
   *  @brief Copy the smallest elements of a sequence using a predicate for
   *         comparison.
   *  @ingroup sorting_algorithms
   *  @param  __first   An input iterator.
   *  @param  __last    Another input iterator.
   *  @param  __result_first   A random-access iterator.
   *  @param  __result_last    Another random-access iterator.
   *  @param  __comp    A comparison functor.
   *  @return   An iterator indicating the end of the resulting sequence.
   *
   *  Copies and sorts the smallest N values from the range @p [__first,__last)
   *  to the range beginning at @p result_first, where the number of
   *  elements to be copied, @p N, is the smaller of @p (__last-__first) and
   *  @p (__result_last-__result_first).
   *  After the sort if @e i and @e j are iterators in the range
   *  @p [__result_first,__result_first+N) such that i precedes j then
   *  @p __comp(*j,*i) is false.
   *  The value returned is @p __result_first+N.
  */
  template<typename _InputIterator, typename _RandomAccessIterator,
	   typename _Compare>
    inline _RandomAccessIterator
    partial_sort_copy(_InputIterator __first, _InputIterator __last,
		      _RandomAccessIterator __result_first,
		      _RandomAccessIterator __result_last,
		      _Compare __comp)
    {
#ifdef _GLIBCXX_CONCEPT_CHECKS
      typedef typename iterator_traits<_InputIterator>::value_type
	_InputValueType;
      typedef typename iterator_traits<_RandomAccessIterator>::value_type
	_OutputValueType;
#endif

// concept requirements
      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
      __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
				  _RandomAccessIterator>)
      __glibcxx_function_requires(_ConvertibleConcept<_InputValueType,
				  _OutputValueType>)
      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
				  _InputValueType, _OutputValueType>)
      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
				  _OutputValueType, _OutputValueType>)
      __glibcxx_requires_valid_range(__first, __last);
      __glibcxx_requires_irreflexive_pred(__first, __last, __comp);
      __glibcxx_requires_valid_range(__result_first, __result_last);

return std::__partial_sort_copy(__first, __last,
				      __result_first, __result_last,
				__gnu_cxx::__ops::__iter_comp_iter(__comp));
    }

/// This is a helper function for the sort routine.
  template<typename _RandomAccessIterator, typename _Compare>
    void
    __unguarded_linear_insert(_RandomAccessIterator __last,
			      _Compare __comp)
    {
      typename iterator_traits<_RandomAccessIterator>::value_type
	__val = _GLIBCXX_MOVE(*__last);
      _RandomAccessIterator __next = __last;
      --__next;
      while (__comp(__val, __next))
	{
	  *__last = _GLIBCXX_MOVE(*__next);
	  __last = __next;
	  --__next;
	}
      *__last = _GLIBCXX_MOVE(__val);
    }

/// This is a helper function for the sort routine.
  template<typename _RandomAccessIterator, typename _Compare>
    void
    __insertion_sort(_RandomAccessIterator __first,
		     _RandomAccessIterator __last, _Compare __comp)
    {
      if (__first == __last) return;

for (_RandomAccessIterator __i = __first + 1; __i != __last; ++__i)
	{
	  if (__comp(__i, __first))
	    {
	      typename iterator_traits<_RandomAccessIterator>::value_type
		__val = _GLIBCXX_MOVE(*__i);
	      _GLIBCXX_MOVE_BACKWARD3(__first, __i, __i + 1);
	      *__first = _GLIBCXX_MOVE(__val);
	    }
	  else
	    std::__unguarded_linear_insert(__i,
				__gnu_cxx::__ops::__val_comp_iter(__comp));
	}
    }

/// This is a helper function for the sort routine.
  template<typename _RandomAccessIterator, typename _Compare>
    inline void
    __unguarded_insertion_sort(_RandomAccessIterator __first,
			       _RandomAccessIterator __last, _Compare __comp)
    {
      for (_RandomAccessIterator __i = __first; __i != __last; ++__i)
	std::__unguarded_linear_insert(__i,
				__gnu_cxx::__ops::__val_comp_iter(__comp));
    }

/**
   *  @doctodo
   *  This controls some aspect of the sort routines.
  */
  enum { _S_threshold = 16 };

/// This is a helper function for the sort routine.
  template<typename _RandomAccessIterator, typename _Compare>
    void
    __final_insertion_sort(_RandomAccessIterator __first,
			   _RandomAccessIterator __last, _Compare __comp)
    {
      if (__last - __first > int(_S_threshold))
	{
	  std::__insertion_sort(__first, __first + int(_S_threshold), __comp);
	  std::__unguarded_insertion_sort(__first + int(_S_threshold), __last,
					  __comp);
	}
      else
	std::__insertion_sort(__first, __last, __comp);
    }

/// This is a helper function...
  template<typename _RandomAccessIterator, typename _Compare>
    _RandomAccessIterator
    __unguarded_partition(_RandomAccessIterator __first,
			  _RandomAccessIterator __last,
			  _RandomAccessIterator __pivot, _Compare __comp)
    {
      while (true)
	{
	  while (__comp(__first, __pivot))
	    ++__first;
	  --__last;
	  while (__comp(__pivot, __last))
	    --__last;
	  if (!(__first < __last))
	    return __first;
	  std::iter_swap(__first, __last);
	  ++__first;
	}
    }

/// This is a helper function...
  template<typename _RandomAccessIterator, typename _Compare>
    inline _RandomAccessIterator
    __unguarded_partition_pivot(_RandomAccessIterator __first,
				_RandomAccessIterator __last, _Compare __comp)
    {
      _RandomAccessIterator __mid = __first + (__last - __first) / 2;
      std::__move_median_to_first(__first, __first + 1, __mid, __last - 1,
				  __comp);
      return std::__unguarded_partition(__first + 1, __last, __first, __comp);
    }

template<typename _RandomAccessIterator, typename _Compare>
    inline void
    __partial_sort(_RandomAccessIterator __first,
		   _RandomAccessIterator __middle,
		   _RandomAccessIterator __last,
		   _Compare __comp)
    {
      std::__heap_select(__first, __middle, __last, __comp);
      std::__sort_heap(__first, __middle, __comp);
    }

/// This is a helper function for the sort routine.
  template<typename _RandomAccessIterator, typename _Size, typename _Compare>
    void
    __introsort_loop(_RandomAccessIterator __first,
		     _RandomAccessIterator __last,
		     _Size __depth_limit, _Compare __comp)
    {
      while (__last - __first > int(_S_threshold))
	{
	  if (__depth_limit == 0)
	    {
	      std::__partial_sort(__first, __last, __last, __comp);
	      return;
	    }
	  --__depth_limit;
	  _RandomAccessIterator __cut =
	    std::__unguarded_partition_pivot(__first, __last, __comp);
	  std::__introsort_loop(__cut, __last, __depth_limit, __comp);
	  __last = __cut;
	}
    }

// sort

template<typename _RandomAccessIterator, typename _Compare>
    inline void
    __sort(_RandomAccessIterator __first, _RandomAccessIterator __last,
	   _Compare __comp)
    {
      if (__first != __last)
	{
	  std::__introsort_loop(__first, __last,
				std::__lg(__last - __first) * 2,
				__comp);
	  std::__final_insertion_sort(__first, __last, __comp);
	}
    }

template<typename _RandomAccessIterator, typename _Size, typename _Compare>
    void
    __introselect(_RandomAccessIterator __first, _RandomAccessIterator __nth,
		  _RandomAccessIterator __last, _Size __depth_limit,
		  _Compare __comp)
    {
      while (__last - __first > 3)
	{
	  if (__depth_limit == 0)
	    {
	      std::__heap_select(__first, __nth + 1, __last, __comp);
	      // Place the nth largest element in its final position.
	      std::iter_swap(__first, __nth);
	      return;
	    }
	  --__depth_limit;
	  _RandomAccessIterator __cut =
	    std::__unguarded_partition_pivot(__first, __last, __comp);
	  if (__cut <= __nth)
	    __first = __cut;
	  else
	    __last = __cut;
	}
      std::__insertion_sort(__first, __last, __comp);
    }

// nth_element

// lower_bound moved to stl_algobase.h

/**
   *  @brief Finds the first position in which @p __val could be inserted
   *         without changing the ordering.
   *  @ingroup binary_search_algorithms
   *  @param  __first   An iterator.
   *  @param  __last    Another iterator.
   *  @param  __val     The search term.
   *  @param  __comp    A functor to use for comparisons.
   *  @return An iterator pointing to the first element <em>not less
   *           than</em> @p __val, or end() if every element is less
   *           than @p __val.
   *  @ingroup binary_search_algorithms
   *
   *  The comparison function should have the same effects on ordering as
   *  the function used for the initial sort.
  */
  template<typename _ForwardIterator, typename _Tp, typename _Compare>
    inline _ForwardIterator
    lower_bound(_ForwardIterator __first, _ForwardIterator __last,
		const _Tp& __val, _Compare __comp)
    {
      // concept requirements
      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
	typename iterator_traits<_ForwardIterator>::value_type, _Tp>)
      __glibcxx_requires_partitioned_lower_pred(__first, __last,
						__val, __comp);

return std::__lower_bound(__first, __last, __val,
				__gnu_cxx::__ops::__iter_comp_val(__comp));
    }

template<typename _ForwardIterator, typename _Tp, typename _Compare>
    _ForwardIterator
    __upper_bound(_ForwardIterator __first, _ForwardIterator __last,
		  const _Tp& __val, _Compare __comp)
    {
      typedef typename iterator_traits<_ForwardIterator>::difference_type
	_DistanceType;

_DistanceType __len = std::distance(__first, __last);

while (__len > 0)
	{
	  _DistanceType __half = __len >> 1;
	  _ForwardIterator __middle = __first;
	  std::advance(__middle, __half);
	  if (__comp(__val, __middle))
	    __len = __half;
	  else
	    {
	      __first = __middle;
	      ++__first;
	      __len = __len - __half - 1;
	    }
	}
      return __first;
    }

/**
   *  @brief Finds the last position in which @p __val could be inserted
   *         without changing the ordering.
   *  @ingroup binary_search_algorithms
   *  @param  __first   An iterator.
   *  @param  __last    Another iterator.
   *  @param  __val     The search term.
   *  @return  An iterator pointing to the first element greater than @p __val,
   *           or end() if no elements are greater than @p __val.
   *  @ingroup binary_search_algorithms
  */
  template<typename _ForwardIterator, typename _Tp>
    inline _ForwardIterator
    upper_bound(_ForwardIterator __first, _ForwardIterator __last,
		const _Tp& __val)
    {
      // concept requirements
      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
      __glibcxx_function_requires(_LessThanOpConcept<
	_Tp, typename iterator_traits<_ForwardIterator>::value_type>)
      __glibcxx_requires_partitioned_upper(__first, __last, __val);

return std::__upper_bound(__first, __last, __val,
				__gnu_cxx::__ops::__val_less_iter());
    }

/**
   *  @brief Finds the last position in which @p __val could be inserted
   *         without changing the ordering.
   *  @ingroup binary_search_algorithms
   *  @param  __first   An iterator.
   *  @param  __last    Another iterator.
   *  @param  __val     The search term.
   *  @param  __comp    A functor to use for comparisons.
   *  @return  An iterator pointing to the first element greater than @p __val,
   *           or end() if no elements are greater than @p __val.
   *  @ingroup binary_search_algorithms
   *
   *  The comparison function should have the same effects on ordering as
   *  the function used for the initial sort.
  */
  template<typename _ForwardIterator, typename _Tp, typename _Compare>
    inline _ForwardIterator
    upper_bound(_ForwardIterator __first, _ForwardIterator __last,
		const _Tp& __val, _Compare __comp)
    {
      // concept requirements
      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
	_Tp, typename iterator_traits<_ForwardIterator>::value_type>)
      __glibcxx_requires_partitioned_upper_pred(__first, __last,
						__val, __comp);

return std::__upper_bound(__first, __last, __val,
				__gnu_cxx::__ops::__val_comp_iter(__comp));
    }

template<typename _ForwardIterator, typename _Tp,
	   typename _CompareItTp, typename _CompareTpIt>
    pair<_ForwardIterator, _ForwardIterator>
    __equal_range(_ForwardIterator __first, _ForwardIterator __last,
		  const _Tp& __val,
		  _CompareItTp __comp_it_val, _CompareTpIt __comp_val_it)
    {
      typedef typename iterator_traits<_ForwardIterator>::difference_type
	_DistanceType;

_DistanceType __len = std::distance(__first, __last);

while (__len > 0)
	{
	  _DistanceType __half = __len >> 1;
	  _ForwardIterator __middle = __first;
	  std::advance(__middle, __half);
	  if (__comp_it_val(__middle, __val))
	    {
	      __first = __middle;
	      ++__first;
	      __len = __len - __half - 1;
	    }
	  else if (__comp_val_it(__val, __middle))
	    __len = __half;
	  else
	    {
	      _ForwardIterator __left
		= std::__lower_bound(__first, __middle, __val, __comp_it_val);
	      std::advance(__first, __len);
	      _ForwardIterator __right
		= std::__upper_bound(++__middle, __first, __val, __comp_val_it);
	      return pair<_ForwardIterator, _ForwardIterator>(__left, __right);
	    }
	}
      return pair<_ForwardIterator, _ForwardIterator>(__first, __first);
    }

/**
   *  @brief Finds the largest subrange in which @p __val could be inserted
   *         at any place in it without changing the ordering.
   *  @ingroup binary_search_algorithms
   *  @param  __first   An iterator.
   *  @param  __last    Another iterator.
   *  @param  __val     The search term.
   *  @return  An pair of iterators defining the subrange.
   *  @ingroup binary_search_algorithms
   *
   *  This is equivalent to
   *  @code
   *    std::make_pair(lower_bound(__first, __last, __val),
   *                   upper_bound(__first, __last, __val))
   *  @endcode
   *  but does not actually call those functions.
  */
  template<typename _ForwardIterator, typename _Tp>
    inline pair<_ForwardIterator, _ForwardIterator>
    equal_range(_ForwardIterator __first, _ForwardIterator __last,
		const _Tp& __val)
    {
      // concept requirements
      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
      __glibcxx_function_requires(_LessThanOpConcept<
	typename iterator_traits<_ForwardIterator>::value_type, _Tp>)
      __glibcxx_function_requires(_LessThanOpConcept<
	_Tp, typename iterator_traits<_ForwardIterator>::value_type>)
      __glibcxx_requires_partitioned_lower(__first, __last, __val);
      __glibcxx_requires_partitioned_upper(__first, __last, __val);

return std::__equal_range(__first, __last, __val,
				__gnu_cxx::__ops::__iter_less_val(),
				__gnu_cxx::__ops::__val_less_iter());
    }

/**
   *  @brief Finds the largest subrange in which @p __val could be inserted
   *         at any place in it without changing the ordering.
   *  @param  __first   An iterator.
   *  @param  __last    Another iterator.
   *  @param  __val     The search term.
   *  @param  __comp    A functor to use for comparisons.
   *  @return  An pair of iterators defining the subrange.
   *  @ingroup binary_search_algorithms
   *
   *  This is equivalent to
   *  @code
   *    std::make_pair(lower_bound(__first, __last, __val, __comp),
   *                   upper_bound(__first, __last, __val, __comp))
   *  @endcode
   *  but does not actually call those functions.
  */
  template<typename _ForwardIterator, typename _Tp, typename _Compare>
    inline pair<_ForwardIterator, _ForwardIterator>
    equal_range(_ForwardIterator __first, _ForwardIterator __last,
		const _Tp& __val, _Compare __comp)
    {
      // concept requirements
      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
	typename iterator_traits<_ForwardIterator>::value_type, _Tp>)
      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
	_Tp, typename iterator_traits<_ForwardIterator>::value_type>)
      __glibcxx_requires_partitioned_lower_pred(__first, __last,
						__val, __comp);
      __glibcxx_requires_partitioned_upper_pred(__first, __last,
						__val, __comp);

return std::__equal_range(__first, __last, __val,
				__gnu_cxx::__ops::__iter_comp_val(__comp),
				__gnu_cxx::__ops::__val_comp_iter(__comp));
    }

/**
   *  @brief Determines whether an element exists in a range.
   *  @ingroup binary_search_algorithms
   *  @param  __first   An iterator.
   *  @param  __last    Another iterator.
   *  @param  __val     The search term.
   *  @return True if @p __val (or its equivalent) is in [@p
   *  __first,@p __last ].
   *
   *  Note that this does not actually return an iterator to @p __val.  For
   *  that, use std::find or a container's specialized find member functions.
  */
  template<typename _ForwardIterator, typename _Tp>
    bool
    binary_search(_ForwardIterator __first, _ForwardIterator __last,
		  const _Tp& __val)
    {
      // concept requirements
      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
      __glibcxx_function_requires(_LessThanOpConcept<
	_Tp, typename iterator_traits<_ForwardIterator>::value_type>)
      __glibcxx_requires_partitioned_lower(__first, __last, __val);
      __glibcxx_requires_partitioned_upper(__first, __last, __val);

_ForwardIterator __i
	= std::__lower_bound(__first, __last, __val,
			     __gnu_cxx::__ops::__iter_less_val());
      return __i != __last && !(__val < *__i);
    }

/**
   *  @brief Determines whether an element exists in a range.
   *  @ingroup binary_search_algorithms
   *  @param  __first   An iterator.
   *  @param  __last    Another iterator.
   *  @param  __val     The search term.
   *  @param  __comp    A functor to use for comparisons.
   *  @return  True if @p __val (or its equivalent) is in @p [__first,__last].
   *
   *  Note that this does not actually return an iterator to @p __val.  For
   *  that, use std::find or a container's specialized find member functions.
   *
   *  The comparison function should have the same effects on ordering as
   *  the function used for the initial sort.
  */
  template<typename _ForwardIterator, typename _Tp, typename _Compare>
    bool
    binary_search(_ForwardIterator __first, _ForwardIterator __last,
		  const _Tp& __val, _Compare __comp)
    {
      // concept requirements
      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
	_Tp, typename iterator_traits<_ForwardIterator>::value_type>)
      __glibcxx_requires_partitioned_lower_pred(__first, __last,
						__val, __comp);
      __glibcxx_requires_partitioned_upper_pred(__first, __last,
						__val, __comp);

_ForwardIterator __i
	= std::__lower_bound(__first, __last, __val,
			     __gnu_cxx::__ops::__iter_comp_val(__comp));
      return __i != __last && !bool(__comp(__val, *__i));
    }

// merge

/// This is a helper function for the __merge_adaptive routines.
  template<typename _InputIterator1, typename _InputIterator2,
	   typename _OutputIterator, typename _Compare>
    void
    __move_merge_adaptive(_InputIterator1 __first1, _InputIterator1 __last1,
			  _InputIterator2 __first2, _InputIterator2 __last2,
			  _OutputIterator __result, _Compare __comp)
    {
      while (__first1 != __last1 && __first2 != __last2)
	{
	  if (__comp(__first2, __first1))
	    {
	      *__result = _GLIBCXX_MOVE(*__first2);
	      ++__first2;
	    }
	  else
	    {
	      *__result = _GLIBCXX_MOVE(*__first1);
	      ++__first1;
	    }
	  ++__result;
	}
      if (__first1 != __last1)
	_GLIBCXX_MOVE3(__first1, __last1, __result);
    }

/// This is a helper function for the __merge_adaptive routines.
  template<typename _BidirectionalIterator1, typename _BidirectionalIterator2,
	   typename _BidirectionalIterator3, typename _Compare>
    void
    __move_merge_adaptive_backward(_BidirectionalIterator1 __first1,
				   _BidirectionalIterator1 __last1,
				   _BidirectionalIterator2 __first2,
				   _BidirectionalIterator2 __last2,
				   _BidirectionalIterator3 __result,
				   _Compare __comp)
    {
      if (__first1 == __last1)
	{
	  _GLIBCXX_MOVE_BACKWARD3(__first2, __last2, __result);
	  return;
	}
      else if (__first2 == __last2)
	return;

--__last1;
      --__last2;
      while (true)
	{
	  if (__comp(__last2, __last1))
	    {
	      *--__result = _GLIBCXX_MOVE(*__last1);
	      if (__first1 == __last1)
		{
		  _GLIBCXX_MOVE_BACKWARD3(__first2, ++__last2, __result);
		  return;
		}
	      --__last1;
	    }
	  else
	    {
	      *--__result = _GLIBCXX_MOVE(*__last2);
	      if (__first2 == __last2)
		return;
	      --__last2;
	    }
	}
    }

/// This is a helper function for the merge routines.
  template<typename _BidirectionalIterator1, typename _BidirectionalIterator2,
	   typename _Distance>
    _BidirectionalIterator1
    __rotate_adaptive(_BidirectionalIterator1 __first,
		      _BidirectionalIterator1 __middle,
		      _BidirectionalIterator1 __last,
		      _Distance __len1, _Distance __len2,
		      _BidirectionalIterator2 __buffer,
		      _Distance __buffer_size)
    {
      _BidirectionalIterator2 __buffer_end;
      if (__len1 > __len2 && __len2 <= __buffer_size)
	{
	  if (__len2)
	    {
	      __buffer_end = _GLIBCXX_MOVE3(__middle, __last, __buffer);
	      _GLIBCXX_MOVE_BACKWARD3(__first, __middle, __last);
	      return _GLIBCXX_MOVE3(__buffer, __buffer_end, __first);
	    }
	  else
	    return __first;
	}
      else if (__len1 <= __buffer_size)
	{
	  if (__len1)
	    {
	      __buffer_end = _GLIBCXX_MOVE3(__first, __middle, __buffer);
	      _GLIBCXX_MOVE3(__middle, __last, __first);
	      return _GLIBCXX_MOVE_BACKWARD3(__buffer, __buffer_end, __last);
	    }
	  else
	    return __last;
	}
      else
	{
	  std::rotate(__first, __middle, __last);
	  std::advance(__first, std::distance(__middle, __last));
	  return __first;
	}
    }

/// This is a helper function for the merge routines.
  template<typename _BidirectionalIterator, typename _Distance, 
	   typename _Pointer, typename _Compare>
    void
    __merge_adaptive(_BidirectionalIterator __first,
		     _BidirectionalIterator __middle,
		     _BidirectionalIterator __last,
		     _Distance __len1, _Distance __len2,
		     _Pointer __buffer, _Distance __buffer_size,
		     _Compare __comp)
    {
      if (__len1 <= __len2 && __len1 <= __buffer_size)
	{
	  _Pointer __buffer_end = _GLIBCXX_MOVE3(__first, __middle, __buffer);
	  std::__move_merge_adaptive(__buffer, __buffer_end, __middle, __last,
				     __first, __comp);
	}
      else if (__len2 <= __buffer_size)
	{
	  _Pointer __buffer_end = _GLIBCXX_MOVE3(__middle, __last, __buffer);
	  std::__move_merge_adaptive_backward(__first, __middle, __buffer,
					      __buffer_end, __last, __comp);
	}
      else
	{
	  _BidirectionalIterator __first_cut = __first;
	  _BidirectionalIterator __second_cut = __middle;
	  _Distance __len11 = 0;
	  _Distance __len22 = 0;
	  if (__len1 > __len2)
	    {
	      __len11 = __len1 / 2;
	      std::advance(__first_cut, __len11);
	      __second_cut
		= std::__lower_bound(__middle, __last, *__first_cut,
				     __gnu_cxx::__ops::__iter_comp_val(__comp));
	      __len22 = std::distance(__middle, __second_cut);
	    }
	  else
	    {
	      __len22 = __len2 / 2;
	      std::advance(__second_cut, __len22);
	      __first_cut
		= std::__upper_bound(__first, __middle, *__second_cut,
				     __gnu_cxx::__ops::__val_comp_iter(__comp));
	      __len11 = std::distance(__first, __first_cut);
	    }

_BidirectionalIterator __new_middle
	    = std::__rotate_adaptive(__first_cut, __middle, __second_cut,
				     __len1 - __len11, __len22, __buffer,
				     __buffer_size);
	  std::__merge_adaptive(__first, __first_cut, __new_middle, __len11,
				__len22, __buffer, __buffer_size, __comp);
	  std::__merge_adaptive(__new_middle, __second_cut, __last,
				__len1 - __len11,
				__len2 - __len22, __buffer,
				__buffer_size, __comp);
	}
    }

/// This is a helper function for the merge routines.
  template<typename _BidirectionalIterator, typename _Distance,
	   typename _Compare>
    void
    __merge_without_buffer(_BidirectionalIterator __first,
			   _BidirectionalIterator __middle,
			   _BidirectionalIterator __last,
			   _Distance __len1, _Distance __len2,
			   _Compare __comp)
    {
      if (__len1 == 0 || __len2 == 0)
	return;

if (__len1 + __len2 == 2)
	{
	  if (__comp(__middle, __first))
	    std::iter_swap(__first, __middle);
	  return;
	}

_BidirectionalIterator __first_cut = __first;
      _BidirectionalIterator __second_cut = __middle;
      _Distance __len11 = 0;
      _Distance __len22 = 0;
      if (__len1 > __len2)
	{
	  __len11 = __len1 / 2;
	  std::advance(__first_cut, __len11);
	  __second_cut
	    = std::__lower_bound(__middle, __last, *__first_cut,
				 __gnu_cxx::__ops::__iter_comp_val(__comp));
	  __len22 = std::distance(__middle, __second_cut);
	}
      else
	{
	  __len22 = __len2 / 2;
	  std::advance(__second_cut, __len22);
	  __first_cut
	    = std::__upper_bound(__first, __middle, *__second_cut,
				 __gnu_cxx::__ops::__val_comp_iter(__comp));
	  __len11 = std::distance(__first, __first_cut);
	}

std::rotate(__first_cut, __middle, __second_cut);
      _BidirectionalIterator __new_middle = __first_cut;
      std::advance(__new_middle, std::distance(__middle, __second_cut));
      std::__merge_without_buffer(__first, __first_cut, __new_middle,
				  __len11, __len22, __comp);
      std::__merge_without_buffer(__new_middle, __second_cut, __last,
				  __len1 - __len11, __len2 - __len22, __comp);
    }

template<typename _BidirectionalIterator, typename _Compare>
    void
    __inplace_merge(_BidirectionalIterator __first,
		    _BidirectionalIterator __middle,
		    _BidirectionalIterator __last,
		    _Compare __comp)
    {
      typedef typename iterator_traits<_BidirectionalIterator>::value_type
	  _ValueType;
      typedef typename iterator_traits<_BidirectionalIterator>::difference_type
	  _DistanceType;

if (__first == __middle || __middle == __last)
	return;

const _DistanceType __len1 = std::distance(__first, __middle);
      const _DistanceType __len2 = std::distance(__middle, __last);

typedef _Temporary_buffer<_BidirectionalIterator, _ValueType> _TmpBuf;
      _TmpBuf __buf(__first, __last);

if (__buf.begin() == 0)
	std::__merge_without_buffer
	  (__first, __middle, __last, __len1, __len2, __comp);
      else
	std::__merge_adaptive
	  (__first, __middle, __last, __len1, __len2, __buf.begin(),
	   _DistanceType(__buf.size()), __comp);
    }

/**
   *  @brief Merges two sorted ranges in place.
   *  @ingroup sorting_algorithms
   *  @param  __first   An iterator.
   *  @param  __middle  Another iterator.
   *  @param  __last    Another iterator.
   *  @return  Nothing.
   *
   *  Merges two sorted and consecutive ranges, [__first,__middle) and
   *  [__middle,__last), and puts the result in [__first,__last).  The
   *  output will be sorted.  The sort is @e stable, that is, for
   *  equivalent elements in the two ranges, elements from the first
   *  range will always come before elements from the second.
   *
   *  If enough additional memory is available, this takes (__last-__first)-1
   *  comparisons.  Otherwise an NlogN algorithm is used, where N is
   *  distance(__first,__last).
  */
  template<typename _BidirectionalIterator>
    inline void
    inplace_merge(_BidirectionalIterator __first,
		  _BidirectionalIterator __middle,
		  _BidirectionalIterator __last)
    {
      // concept requirements
      __glibcxx_function_requires(_Mutable_BidirectionalIteratorConcept<
	    _BidirectionalIterator>)
      __glibcxx_function_requires(_LessThanComparableConcept<
	    typename iterator_traits<_BidirectionalIterator>::value_type>)
      __glibcxx_requires_sorted(__first, __middle);
      __glibcxx_requires_sorted(__middle, __last);
      __glibcxx_requires_irreflexive(__first, __last);

std::__inplace_merge(__first, __middle, __last,
			   __gnu_cxx::__ops::__iter_less_iter());
    }

/**
   *  @brief Merges two sorted ranges in place.
   *  @ingroup sorting_algorithms
   *  @param  __first   An iterator.
   *  @param  __middle  Another iterator.
   *  @param  __last    Another iterator.
   *  @param  __comp    A functor to use for comparisons.
   *  @return  Nothing.
   *
   *  Merges two sorted and consecutive ranges, [__first,__middle) and
   *  [middle,last), and puts the result in [__first,__last).  The output will
   *  be sorted.  The sort is @e stable, that is, for equivalent
   *  elements in the two ranges, elements from the first range will always
   *  come before elements from the second.
   *
   *  If enough additional memory is available, this takes (__last-__first)-1
   *  comparisons.  Otherwise an NlogN algorithm is used, where N is
   *  distance(__first,__last).
   *
   *  The comparison function should have the same effects on ordering as
   *  the function used for the initial sort.
  */
  template<typename _BidirectionalIterator, typename _Compare>
    inline void
    inplace_merge(_BidirectionalIterator __first,
		  _BidirectionalIterator __middle,
		  _BidirectionalIterator __last,
		  _Compare __comp)
    {
      // concept requirements
      __glibcxx_function_requires(_Mutable_BidirectionalIteratorConcept<
	    _BidirectionalIterator>)
      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
	    typename iterator_traits<_BidirectionalIterator>::value_type,
	    typename iterator_traits<_BidirectionalIterator>::value_type>)
      __glibcxx_requires_sorted_pred(__first, __middle, __comp);
      __glibcxx_requires_sorted_pred(__middle, __last, __comp);
      __glibcxx_requires_irreflexive_pred(__first, __last, __comp);

std::__inplace_merge(__first, __middle, __last,
			   __gnu_cxx::__ops::__iter_comp_iter(__comp));
    }

/// This is a helper function for the __merge_sort_loop routines.
  template<typename _InputIterator, typename _OutputIterator,
	   typename _Compare>
    _OutputIterator
    __move_merge(_InputIterator __first1, _InputIterator __last1,
		 _InputIterator __first2, _InputIterator __last2,
		 _OutputIterator __result, _Compare __comp)
    {
      while (__first1 != __last1 && __first2 != __last2)
	{
	  if (__comp(__first2, __first1))
	    {
	      *__result = _GLIBCXX_MOVE(*__first2);
	      ++__first2;
	    }
	  else
	    {
	      *__result = _GLIBCXX_MOVE(*__first1);
	      ++__first1;
	    }
	  ++__result;
	}
      return _GLIBCXX_MOVE3(__first2, __last2,
			    _GLIBCXX_MOVE3(__first1, __last1,
					   __result));
    }

template<typename _RandomAccessIterator1, typename _RandomAccessIterator2,
	   typename _Distance, typename _Compare>
    void
    __merge_sort_loop(_RandomAccessIterator1 __first,
		      _RandomAccessIterator1 __last,
		      _RandomAccessIterator2 __result, _Distance __step_size,
		      _Compare __comp)
    {
      const _Distance __two_step = 2 * __step_size;

while (__last - __first >= __two_step)
	{
	  __result = std::__move_merge(__first, __first + __step_size,
				       __first + __step_size,
				       __first + __two_step,
				       __result, __comp);
	  __first += __two_step;
	}
      __step_size = std::min(_Distance(__last - __first), __step_size);

std::__move_merge(__first, __first + __step_size,
			__first + __step_size, __last, __result, __comp);
    }

template<typename _RandomAccessIterator, typename _Distance,
	   typename _Compare>
    void
    __chunk_insertion_sort(_RandomAccessIterator __first,
			   _RandomAccessIterator __last,
			   _Distance __chunk_size, _Compare __comp)
    {
      while (__last - __first >= __chunk_size)
	{
	  std::__insertion_sort(__first, __first + __chunk_size, __comp);
	  __first += __chunk_size;
	}
      std::__insertion_sort(__first, __last, __comp);
    }

enum { _S_chunk_size = 7 };

template<typename _RandomAccessIterator, typename _Pointer, typename _Compare>
    void
    __merge_sort_with_buffer(_RandomAccessIterator __first,
			     _RandomAccessIterator __last,
			     _Pointer __buffer, _Compare __comp)
    {
      typedef typename iterator_traits<_RandomAccessIterator>::difference_type
	_Distance;

const _Distance __len = __last - __first;
      const _Pointer __buffer_last = __buffer + __len;

_Distance __step_size = _S_chunk_size;
      std::__chunk_insertion_sort(__first, __last, __step_size, __comp);

while (__step_size < __len)
	{
	  std::__merge_sort_loop(__first, __last, __buffer,
				 __step_size, __comp);
	  __step_size *= 2;
	  std::__merge_sort_loop(__buffer, __buffer_last, __first,
				 __step_size, __comp);
	  __step_size *= 2;
	}
    }

template<typename _RandomAccessIterator, typename _Pointer,
	   typename _Distance, typename _Compare>
    void
    __stable_sort_adaptive(_RandomAccessIterator __first,
			   _RandomAccessIterator __last,
			   _Pointer __buffer, _Distance __buffer_size,
			   _Compare __comp)
    {
      const _Distance __len = (__last - __first + 1) / 2;
      const _RandomAccessIterator __middle = __first + __len;
      if (__len > __buffer_size)
	{
	  std::__stable_sort_adaptive(__first, __middle, __buffer,
				      __buffer_size, __comp);
	  std::__stable_sort_adaptive(__middle, __last, __buffer,
				      __buffer_size, __comp);
	}
      else
	{
	  std::__merge_sort_with_buffer(__first, __middle, __buffer, __comp);
	  std::__merge_sort_with_buffer(__middle, __last, __buffer, __comp);
	}
      std::__merge_adaptive(__first, __middle, __last,
			    _Distance(__middle - __first),
			    _Distance(__last - __middle),
			    __buffer, __buffer_size,
			    __comp);
    }

/// This is a helper function for the stable sorting routines.
  template<typename _RandomAccessIterator, typename _Compare>
    void
    __inplace_stable_sort(_RandomAccessIterator __first,
			  _RandomAccessIterator __last, _Compare __comp)
    {
      if (__last - __first < 15)
	{
	  std::__insertion_sort(__first, __last, __comp);
	  return;
	}
      _RandomAccessIterator __middle = __first + (__last - __first) / 2;
      std::__inplace_stable_sort(__first, __middle, __comp);
      std::__inplace_stable_sort(__middle, __last, __comp);
      std::__merge_without_buffer(__first, __middle, __last,
				  __middle - __first,
				  __last - __middle,
				  __comp);
    }

// stable_sort

// Set algorithms: includes, set_union, set_intersection, set_difference,
  // set_symmetric_difference.  All of these algorithms have the precondition
  // that their input ranges are sorted and the postcondition that their output
  // ranges are sorted.

template<typename _InputIterator1, typename _InputIterator2,
	   typename _Compare>
    bool
    __includes(_InputIterator1 __first1, _InputIterator1 __last1,
	       _InputIterator2 __first2, _InputIterator2 __last2,
	       _Compare __comp)
    {
      while (__first1 != __last1 && __first2 != __last2)
	if (__comp(__first2, __first1))
	  return false;
	else if (__comp(__first1, __first2))
	  ++__first1;
	else
	  {
	    ++__first1;
	    ++__first2;
	  }

return __first2 == __last2;
    }

/**
   *  @brief Determines whether all elements of a sequence exists in a range.
   *  @param  __first1  Start of search range.
   *  @param  __last1   End of search range.
   *  @param  __first2  Start of sequence
   *  @param  __last2   End of sequence.
   *  @return  True if each element in [__first2,__last2) is contained in order
   *  within [__first1,__last1).  False otherwise.
   *  @ingroup set_algorithms
   *
   *  This operation expects both [__first1,__last1) and
   *  [__first2,__last2) to be sorted.  Searches for the presence of
   *  each element in [__first2,__last2) within [__first1,__last1).
   *  The iterators over each range only move forward, so this is a
   *  linear algorithm.  If an element in [__first2,__last2) is not
   *  found before the search iterator reaches @p __last2, false is
   *  returned.
  */
  template<typename _InputIterator1, typename _InputIterator2>
    inline bool
    includes(_InputIterator1 __first1, _InputIterator1 __last1,
	     _InputIterator2 __first2, _InputIterator2 __last2)
    {
      // concept requirements
      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
      __glibcxx_function_requires(_LessThanOpConcept<
	    typename iterator_traits<_InputIterator1>::value_type,
	    typename iterator_traits<_InputIterator2>::value_type>)
      __glibcxx_function_requires(_LessThanOpConcept<
	    typename iterator_traits<_InputIterator2>::value_type,
	    typename iterator_traits<_InputIterator1>::value_type>)
      __glibcxx_requires_sorted_set(__first1, __last1, __first2);
      __glibcxx_requires_sorted_set(__first2, __last2, __first1);
      __glibcxx_requires_irreflexive2(__first1, __last1);
      __glibcxx_requires_irreflexive2(__first2, __last2);

return std::__includes(__first1, __last1, __first2, __last2,
			     __gnu_cxx::__ops::__iter_less_iter());
    }

/**
   *  @brief Determines whether all elements of a sequence exists in a range
   *  using comparison.
   *  @ingroup set_algorithms
   *  @param  __first1  Start of search range.
   *  @param  __last1   End of search range.
   *  @param  __first2  Start of sequence
   *  @param  __last2   End of sequence.
   *  @param  __comp    Comparison function to use.
   *  @return True if each element in [__first2,__last2) is contained
   *  in order within [__first1,__last1) according to comp.  False
   *  otherwise.  @ingroup set_algorithms
   *
   *  This operation expects both [__first1,__last1) and
   *  [__first2,__last2) to be sorted.  Searches for the presence of
   *  each element in [__first2,__last2) within [__first1,__last1),
   *  using comp to decide.  The iterators over each range only move
   *  forward, so this is a linear algorithm.  If an element in
   *  [__first2,__last2) is not found before the search iterator
   *  reaches @p __last2, false is returned.
  */
  template<typename _InputIterator1, typename _InputIterator2,
	   typename _Compare>
    inline bool
    includes(_InputIterator1 __first1, _InputIterator1 __last1,
	     _InputIterator2 __first2, _InputIterator2 __last2,
	     _Compare __comp)
    {
      // concept requirements
      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
	    typename iterator_traits<_InputIterator1>::value_type,
	    typename iterator_traits<_InputIterator2>::value_type>)
      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
	    typename iterator_traits<_InputIterator2>::value_type,
	    typename iterator_traits<_InputIterator1>::value_type>)
      __glibcxx_requires_sorted_set_pred(__first1, __last1, __first2, __comp);
      __glibcxx_requires_sorted_set_pred(__first2, __last2, __first1, __comp);
      __glibcxx_requires_irreflexive_pred2(__first1, __last1, __comp);
      __glibcxx_requires_irreflexive_pred2(__first2, __last2, __comp);

return std::__includes(__first1, __last1, __first2, __last2,
			     __gnu_cxx::__ops::__iter_comp_iter(__comp));
    }

// nth_element
  // merge
  // set_difference
  // set_intersection
  // set_union
  // stable_sort
  // set_symmetric_difference
  // min_element
  // max_element

template<typename _BidirectionalIterator, typename _Compare>
    bool
    __next_permutation(_BidirectionalIterator __first,
		       _BidirectionalIterator __last, _Compare __comp)
    {
      if (__first == __last)
	return false;
      _BidirectionalIterator __i = __first;
      ++__i;
      if (__i == __last)
	return false;
      __i = __last;
      --__i;

for(;;)
	{
	  _BidirectionalIterator __ii = __i;
	  --__i;
	  if (__comp(__i, __ii))
	    {
	      _BidirectionalIterator __j = __last;
	      while (!__comp(__i, --__j))
		{}
	      std::iter_swap(__i, __j);
	      std::__reverse(__ii, __last,
			     std::__iterator_category(__first));
	      return true;
	    }
	  if (__i == __first)
	    {
	      std::__reverse(__first, __last,
			     std::__iterator_category(__first));
	      return false;
	    }
	}
    }

/**
   *  @brief  Permute range into the next @e dictionary ordering.
   *  @ingroup sorting_algorithms
   *  @param  __first  Start of range.
   *  @param  __last   End of range.
   *  @return  False if wrapped to first permutation, true otherwise.
   *
   *  Treats all permutations of the range as a set of @e dictionary sorted
   *  sequences.  Permutes the current sequence into the next one of this set.
   *  Returns true if there are more sequences to generate.  If the sequence
   *  is the largest of the set, the smallest is generated and false returned.
  */
  template<typename _BidirectionalIterator>
    inline bool
    next_permutation(_BidirectionalIterator __first,
		     _BidirectionalIterator __last)
    {
      // concept requirements
      __glibcxx_function_requires(_BidirectionalIteratorConcept<
				  _BidirectionalIterator>)
      __glibcxx_function_requires(_LessThanComparableConcept<
	    typename iterator_traits<_BidirectionalIterator>::value_type>)
      __glibcxx_requires_valid_range(__first, __last);
      __glibcxx_requires_irreflexive(__first, __last);

return std::__next_permutation
	(__first, __last, __gnu_cxx::__ops::__iter_less_iter());
    }

/**
   *  @brief  Permute range into the next @e dictionary ordering using
   *          comparison functor.
   *  @ingroup sorting_algorithms
   *  @param  __first  Start of range.
   *  @param  __last   End of range.
   *  @param  __comp   A comparison functor.
   *  @return  False if wrapped to first permutation, true otherwise.
   *
   *  Treats all permutations of the range [__first,__last) as a set of
   *  @e dictionary sorted sequences ordered by @p __comp.  Permutes the current
   *  sequence into the next one of this set.  Returns true if there are more
   *  sequences to generate.  If the sequence is the largest of the set, the
   *  smallest is generated and false returned.
  */
  template<typename _BidirectionalIterator, typename _Compare>
    inline bool
    next_permutation(_BidirectionalIterator __first,
		     _BidirectionalIterator __last, _Compare __comp)
    {
      // concept requirements
      __glibcxx_function_requires(_BidirectionalIteratorConcept<
				  _BidirectionalIterator>)
      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
	    typename iterator_traits<_BidirectionalIterator>::value_type,
	    typename iterator_traits<_BidirectionalIterator>::value_type>)
      __glibcxx_requires_valid_range(__first, __last);
      __glibcxx_requires_irreflexive_pred(__first, __last, __comp);

return std::__next_permutation
	(__first, __last, __gnu_cxx::__ops::__iter_comp_iter(__comp));
    }

template<typename _BidirectionalIterator, typename _Compare>
    bool
    __prev_permutation(_BidirectionalIterator __first,
		       _BidirectionalIterator __last, _Compare __comp)
    {
      if (__first == __last)
	return false;
      _BidirectionalIterator __i = __first;
      ++__i;
      if (__i == __last)
	return false;
      __i = __last;
      --__i;

for(;;)
	{
	  _BidirectionalIterator __ii = __i;
	  --__i;
	  if (__comp(__ii, __i))
	    {
	      _BidirectionalIterator __j = __last;
	      while (!__comp(--__j, __i))
		{}
	      std::iter_swap(__i, __j);
	      std::__reverse(__ii, __last,
			     std::__iterator_category(__first));
	      return true;
	    }
	  if (__i == __first)
	    {
	      std::__reverse(__first, __last,
			     std::__iterator_category(__first));
	      return false;
	    }
	}
    }

/**
   *  @brief  Permute range into the previous @e dictionary ordering.
   *  @ingroup sorting_algorithms
   *  @param  __first  Start of range.
   *  @param  __last   End of range.
   *  @return  False if wrapped to last permutation, true otherwise.
   *
   *  Treats all permutations of the range as a set of @e dictionary sorted
   *  sequences.  Permutes the current sequence into the previous one of this
   *  set.  Returns true if there are more sequences to generate.  If the
   *  sequence is the smallest of the set, the largest is generated and false
   *  returned.
  */
  template<typename _BidirectionalIterator>
    inline bool
    prev_permutation(_BidirectionalIterator __first,
		     _BidirectionalIterator __last)
    {
      // concept requirements
      __glibcxx_function_requires(_BidirectionalIteratorConcept<
				  _BidirectionalIterator>)
      __glibcxx_function_requires(_LessThanComparableConcept<
	    typename iterator_traits<_BidirectionalIterator>::value_type>)
      __glibcxx_requires_valid_range(__first, __last);
      __glibcxx_requires_irreflexive(__first, __last);

return std::__prev_permutation(__first, __last,
				     __gnu_cxx::__ops::__iter_less_iter());
    }

/**
   *  @brief  Permute range into the previous @e dictionary ordering using
   *          comparison functor.
   *  @ingroup sorting_algorithms
   *  @param  __first  Start of range.
   *  @param  __last   End of range.
   *  @param  __comp   A comparison functor.
   *  @return  False if wrapped to last permutation, true otherwise.
   *
   *  Treats all permutations of the range [__first,__last) as a set of
   *  @e dictionary sorted sequences ordered by @p __comp.  Permutes the current
   *  sequence into the previous one of this set.  Returns true if there are
   *  more sequences to generate.  If the sequence is the smallest of the set,
   *  the largest is generated and false returned.
  */
  template<typename _BidirectionalIterator, typename _Compare>
    inline bool
    prev_permutation(_BidirectionalIterator __first,
		     _BidirectionalIterator __last, _Compare __comp)
    {
      // concept requirements
      __glibcxx_function_requires(_BidirectionalIteratorConcept<
				  _BidirectionalIterator>)
      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
	    typename iterator_traits<_BidirectionalIterator>::value_type,
	    typename iterator_traits<_BidirectionalIterator>::value_type>)
      __glibcxx_requires_valid_range(__first, __last);
      __glibcxx_requires_irreflexive_pred(__first, __last, __comp);

return std::__prev_permutation(__first, __last,
				__gnu_cxx::__ops::__iter_comp_iter(__comp));
    }

// replace
  // replace_if

template<typename _InputIterator, typename _OutputIterator,
	   typename _Predicate, typename _Tp>
    _OutputIterator
    __replace_copy_if(_InputIterator __first, _InputIterator __last,
		      _OutputIterator __result,
		      _Predicate __pred, const _Tp& __new_value)
    {
      for (; __first != __last; ++__first, (void)++__result)
	if (__pred(__first))
	  *__result = __new_value;
	else
	  *__result = *__first;
      return __result;
    }

/**
   *  @brief Copy a sequence, replacing each element of one value with another
   *         value.
   *  @param  __first      An input iterator.
   *  @param  __last       An input iterator.
   *  @param  __result     An output iterator.
   *  @param  __old_value  The value to be replaced.
   *  @param  __new_value  The replacement value.
   *  @return   The end of the output sequence, @p result+(last-first).
   *
   *  Copies each element in the input range @p [__first,__last) to the
   *  output range @p [__result,__result+(__last-__first)) replacing elements
   *  equal to @p __old_value with @p __new_value.
  */
  template<typename _InputIterator, typename _OutputIterator, typename _Tp>
    inline _OutputIterator
    replace_copy(_InputIterator __first, _InputIterator __last,
		 _OutputIterator __result,
		 const _Tp& __old_value, const _Tp& __new_value)
    {
      // concept requirements
      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
	    typename iterator_traits<_InputIterator>::value_type>)
      __glibcxx_function_requires(_EqualOpConcept<
	    typename iterator_traits<_InputIterator>::value_type, _Tp>)
      __glibcxx_requires_valid_range(__first, __last);

return std::__replace_copy_if(__first, __last, __result,
			__gnu_cxx::__ops::__iter_equals_val(__old_value),
					      __new_value);
    }

/**
   *  @brief Copy a sequence, replacing each value for which a predicate
   *         returns true with another value.
   *  @ingroup mutating_algorithms
   *  @param  __first      An input iterator.
   *  @param  __last       An input iterator.
   *  @param  __result     An output iterator.
   *  @param  __pred       A predicate.
   *  @param  __new_value  The replacement value.
   *  @return   The end of the output sequence, @p __result+(__last-__first).
   *
   *  Copies each element in the range @p [__first,__last) to the range
   *  @p [__result,__result+(__last-__first)) replacing elements for which
   *  @p __pred returns true with @p __new_value.
  */
  template<typename _InputIterator, typename _OutputIterator,
	   typename _Predicate, typename _Tp>
    inline _OutputIterator
    replace_copy_if(_InputIterator __first, _InputIterator __last,
		    _OutputIterator __result,
		    _Predicate __pred, const _Tp& __new_value)
    {
      // concept requirements
      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
	    typename iterator_traits<_InputIterator>::value_type>)
      __glibcxx_function_requires(_UnaryPredicateConcept<_Predicate,
	    typename iterator_traits<_InputIterator>::value_type>)
      __glibcxx_requires_valid_range(__first, __last);

return std::__replace_copy_if(__first, __last, __result,
				__gnu_cxx::__ops::__pred_iter(__pred),
					      __new_value);
    }

template<typename _InputIterator, typename _Predicate>
    typename iterator_traits<_InputIterator>::difference_type
    __count_if(_InputIterator __first, _InputIterator __last, _Predicate __pred)
    {
      typename iterator_traits<_InputIterator>::difference_type __n = 0;
      for (; __first != __last; ++__first)
	if (__pred(__first))
	  ++__n;
      return __n;
    }

#if __cplusplus >= 201103L
  /**
   *  @brief  Determines whether the elements of a sequence are sorted.
   *  @ingroup sorting_algorithms
   *  @param  __first   An iterator.
   *  @param  __last    Another iterator.
   *  @return  True if the elements are sorted, false otherwise.
  */
  template<typename _ForwardIterator>
    inline bool
    is_sorted(_ForwardIterator __first, _ForwardIterator __last)
    { return std::is_sorted_until(__first, __last) == __last; }

/**
   *  @brief  Determines whether the elements of a sequence are sorted
   *          according to a comparison functor.
   *  @ingroup sorting_algorithms
   *  @param  __first   An iterator.
   *  @param  __last    Another iterator.
   *  @param  __comp    A comparison functor.
   *  @return  True if the elements are sorted, false otherwise.
  */
  template<typename _ForwardIterator, typename _Compare>
    inline bool
    is_sorted(_ForwardIterator __first, _ForwardIterator __last,
	      _Compare __comp)
    { return std::is_sorted_until(__first, __last, __comp) == __last; }

template<typename _ForwardIterator, typename _Compare>
    _ForwardIterator
    __is_sorted_until(_ForwardIterator __first, _ForwardIterator __last,
		      _Compare __comp)
    {
      if (__first == __last)
	return __last;

_ForwardIterator __next = __first;
      for (++__next; __next != __last; __first = __next, (void)++__next)
	if (__comp(__next, __first))
	  return __next;
      return __next;
    }

/**
   *  @brief  Determines the end of a sorted sequence.
   *  @ingroup sorting_algorithms
   *  @param  __first   An iterator.
   *  @param  __last    Another iterator.
   *  @return  An iterator pointing to the last iterator i in [__first, __last)
   *           for which the range [__first, i) is sorted.
  */
  template<typename _ForwardIterator>
    inline _ForwardIterator
    is_sorted_until(_ForwardIterator __first, _ForwardIterator __last)
    {
      // concept requirements
      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
      __glibcxx_function_requires(_LessThanComparableConcept<
	    typename iterator_traits<_ForwardIterator>::value_type>)
      __glibcxx_requires_valid_range(__first, __last);
      __glibcxx_requires_irreflexive(__first, __last);

return std::__is_sorted_until(__first, __last,
				    __gnu_cxx::__ops::__iter_less_iter());
    }

/**
   *  @brief  Determines the end of a sorted sequence using comparison functor.
   *  @ingroup sorting_algorithms
   *  @param  __first   An iterator.
   *  @param  __last    Another iterator.
   *  @param  __comp    A comparison functor.
   *  @return  An iterator pointing to the last iterator i in [__first, __last)
   *           for which the range [__first, i) is sorted.
  */
  template<typename _ForwardIterator, typename _Compare>
    inline _ForwardIterator
    is_sorted_until(_ForwardIterator __first, _ForwardIterator __last,
		    _Compare __comp)
    {
      // concept requirements
      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
	    typename iterator_traits<_ForwardIterator>::value_type,
	    typename iterator_traits<_ForwardIterator>::value_type>)
      __glibcxx_requires_valid_range(__first, __last);
      __glibcxx_requires_irreflexive_pred(__first, __last, __comp);

return std::__is_sorted_until(__first, __last,
				    __gnu_cxx::__ops::__iter_comp_iter(__comp));
    }

/**
   *  @brief  Determines min and max at once as an ordered pair.
   *  @ingroup sorting_algorithms
   *  @param  __a  A thing of arbitrary type.
   *  @param  __b  Another thing of arbitrary type.
   *  @return A pair(__b, __a) if __b is smaller than __a, pair(__a,
   *  __b) otherwise.
  */
  template<typename _Tp>
    _GLIBCXX14_CONSTEXPR
    inline pair<const _Tp&, const _Tp&>
    minmax(const _Tp& __a, const _Tp& __b)
    {
      // concept requirements
      __glibcxx_function_requires(_LessThanComparableConcept<_Tp>)

return __b < __a ? pair<const _Tp&, const _Tp&>(__b, __a)
		       : pair<const _Tp&, const _Tp&>(__a, __b);
    }

/**
   *  @brief  Determines min and max at once as an ordered pair.
   *  @ingroup sorting_algorithms
   *  @param  __a  A thing of arbitrary type.
   *  @param  __b  Another thing of arbitrary type.
   *  @param  __comp  A @link comparison_functors comparison functor @endlink.
   *  @return A pair(__b, __a) if __b is smaller than __a, pair(__a,
   *  __b) otherwise.
  */
  template<typename _Tp, typename _Compare>
    _GLIBCXX14_CONSTEXPR
    inline pair<const _Tp&, const _Tp&>
    minmax(const _Tp& __a, const _Tp& __b, _Compare __comp)
    {
      return __comp(__b, __a) ? pair<const _Tp&, const _Tp&>(__b, __a)
			      : pair<const _Tp&, const _Tp&>(__a, __b);
    }

template<typename _ForwardIterator, typename _Compare>
    _GLIBCXX14_CONSTEXPR
    pair<_ForwardIterator, _ForwardIterator>
    __minmax_element(_ForwardIterator __first, _ForwardIterator __last,
		     _Compare __comp)
    {
      _ForwardIterator __next = __first;
      if (__first == __last
	  || ++__next == __last)
	return std::make_pair(__first, __first);

_ForwardIterator __min{}, __max{};
      if (__comp(__next, __first))
	{
	  __min = __next;
	  __max = __first;
	}
      else
	{
	  __min = __first;
	  __max = __next;
	}

__first = __next;
      ++__first;

while (__first != __last)
	{
	  __next = __first;
	  if (++__next == __last)
	    {
	      if (__comp(__first, __min))
		__min = __first;
	      else if (!__comp(__first, __max))
		__max = __first;
	      break;
	    }

if (__comp(__next, __first))
	    {
	      if (__comp(__next, __min))
		__min = __next;
	      if (!__comp(__first, __max))
		__max = __first;
	    }
	  else
	    {
	      if (__comp(__first, __min))
		__min = __first;
	      if (!__comp(__next, __max))
		__max = __next;
	    }

__first = __next;
	  ++__first;
	}

return std::make_pair(__min, __max);
    }

/**
   *  @brief  Return a pair of iterators pointing to the minimum and maximum
   *          elements in a range.
   *  @ingroup sorting_algorithms
   *  @param  __first  Start of range.
   *  @param  __last   End of range.
   *  @return  make_pair(m, M), where m is the first iterator i in 
   *           [__first, __last) such that no other element in the range is
   *           smaller, and where M is the last iterator i in [__first, __last)
   *           such that no other element in the range is larger.
  */
  template<typename _ForwardIterator>
    _GLIBCXX14_CONSTEXPR
    inline pair<_ForwardIterator, _ForwardIterator>
    minmax_element(_ForwardIterator __first, _ForwardIterator __last)
    {
      // concept requirements
      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
      __glibcxx_function_requires(_LessThanComparableConcept<
	    typename iterator_traits<_ForwardIterator>::value_type>)
      __glibcxx_requires_valid_range(__first, __last);
      __glibcxx_requires_irreflexive(__first, __last);

return std::__minmax_element(__first, __last,
				   __gnu_cxx::__ops::__iter_less_iter());
    }

/**
   *  @brief  Return a pair of iterators pointing to the minimum and maximum
   *          elements in a range.
   *  @ingroup sorting_algorithms
   *  @param  __first  Start of range.
   *  @param  __last   End of range.
   *  @param  __comp   Comparison functor.
   *  @return  make_pair(m, M), where m is the first iterator i in 
   *           [__first, __last) such that no other element in the range is
   *           smaller, and where M is the last iterator i in [__first, __last)
   *           such that no other element in the range is larger.
  */
  template<typename _ForwardIterator, typename _Compare>
    _GLIBCXX14_CONSTEXPR
    inline pair<_ForwardIterator, _ForwardIterator>
    minmax_element(_ForwardIterator __first, _ForwardIterator __last,
		   _Compare __comp)
    {
      // concept requirements
      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
	    typename iterator_traits<_ForwardIterator>::value_type,
	    typename iterator_traits<_ForwardIterator>::value_type>)
      __glibcxx_requires_valid_range(__first, __last);
      __glibcxx_requires_irreflexive_pred(__first, __last, __comp);

return std::__minmax_element(__first, __last,
				   __gnu_cxx::__ops::__iter_comp_iter(__comp));
    }

// N2722 + DR 915.
  template<typename _Tp>
    _GLIBCXX14_CONSTEXPR
    inline _Tp
    min(initializer_list<_Tp> __l)
    { return *std::min_element(__l.begin(), __l.end()); }

template<typename _Tp, typename _Compare>
    _GLIBCXX14_CONSTEXPR
    inline _Tp
    min(initializer_list<_Tp> __l, _Compare __comp)
    { return *std::min_element(__l.begin(), __l.end(), __comp); }

template<typename _Tp>
    _GLIBCXX14_CONSTEXPR
    inline _Tp
    max(initializer_list<_Tp> __l)
    { return *std::max_element(__l.begin(), __l.end()); }

template<typename _Tp, typename _Compare>
    _GLIBCXX14_CONSTEXPR
    inline _Tp
    max(initializer_list<_Tp> __l, _Compare __comp)
    { return *std::max_element(__l.begin(), __l.end(), __comp); }

template<typename _Tp>
    _GLIBCXX14_CONSTEXPR
    inline pair<_Tp, _Tp>
    minmax(initializer_list<_Tp> __l)
    {
      pair<const _Tp*, const _Tp*> __p =
	std::minmax_element(__l.begin(), __l.end());
      return std::make_pair(*__p.first, *__p.second);
    }

template<typename _Tp, typename _Compare>
    _GLIBCXX14_CONSTEXPR
    inline pair<_Tp, _Tp>
    minmax(initializer_list<_Tp> __l, _Compare __comp)
    {
      pair<const _Tp*, const _Tp*> __p =
	std::minmax_element(__l.begin(), __l.end(), __comp);
      return std::make_pair(*__p.first, *__p.second);
    }

template<typename _ForwardIterator1, typename _ForwardIterator2,
	   typename _BinaryPredicate>
    bool
    __is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
		     _ForwardIterator2 __first2, _BinaryPredicate __pred)
    {
      // Efficiently compare identical prefixes:  O(N) if sequences
      // have the same elements in the same order.
      for (; __first1 != __last1; ++__first1, (void)++__first2)
	if (!__pred(__first1, __first2))
	  break;

if (__first1 == __last1)
	return true;

// Establish __last2 assuming equal ranges by iterating over the
      // rest of the list.
      _ForwardIterator2 __last2 = __first2;
      std::advance(__last2, std::distance(__first1, __last1));
      for (_ForwardIterator1 __scan = __first1; __scan != __last1; ++__scan)
	{
	  if (__scan != std::__find_if(__first1, __scan,
			  __gnu_cxx::__ops::__iter_comp_iter(__pred, __scan)))
	    continue; // We've seen this one before.
	  
	  auto __matches
	    = std::__count_if(__first2, __last2,
			__gnu_cxx::__ops::__iter_comp_iter(__pred, __scan));
	  if (0 == __matches ||
	      std::__count_if(__scan, __last1,
			__gnu_cxx::__ops::__iter_comp_iter(__pred, __scan))
	      != __matches)
	    return false;
	}
      return true;
    }

/**
   *  @brief  Checks whether a permutation of the second sequence is equal
   *          to the first sequence.
   *  @ingroup non_mutating_algorithms
   *  @param  __first1  Start of first range.
   *  @param  __last1   End of first range.
   *  @param  __first2  Start of second range.
   *  @return true if there exists a permutation of the elements in the range
   *          [__first2, __first2 + (__last1 - __first1)), beginning with 
   *          ForwardIterator2 begin, such that equal(__first1, __last1, begin)
   *          returns true; otherwise, returns false.
  */
  template<typename _ForwardIterator1, typename _ForwardIterator2>
    inline bool
    is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
		   _ForwardIterator2 __first2)
    {
      // concept requirements
      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator1>)
      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator2>)
      __glibcxx_function_requires(_EqualOpConcept<
		typename iterator_traits<_ForwardIterator1>::value_type,
		typename iterator_traits<_ForwardIterator2>::value_type>)
      __glibcxx_requires_valid_range(__first1, __last1);

return std::__is_permutation(__first1, __last1, __first2,
				   __gnu_cxx::__ops::__iter_equal_to_iter());
    }

/**
   *  @brief  Checks whether a permutation of the second sequence is equal
   *          to the first sequence.
   *  @ingroup non_mutating_algorithms
   *  @param  __first1  Start of first range.
   *  @param  __last1   End of first range.
   *  @param  __first2  Start of second range.
   *  @param  __pred    A binary predicate.
   *  @return true if there exists a permutation of the elements in
   *          the range [__first2, __first2 + (__last1 - __first1)),
   *          beginning with ForwardIterator2 begin, such that
   *          equal(__first1, __last1, __begin, __pred) returns true;
   *          otherwise, returns false.
  */
  template<typename _ForwardIterator1, typename _ForwardIterator2,
	   typename _BinaryPredicate>
    inline bool
    is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
		   _ForwardIterator2 __first2, _BinaryPredicate __pred)
    {
      // concept requirements
      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator1>)
      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator2>)
      __glibcxx_function_requires(_BinaryPredicateConcept<_BinaryPredicate,
	    typename iterator_traits<_ForwardIterator1>::value_type,
	    typename iterator_traits<_ForwardIterator2>::value_type>)
      __glibcxx_requires_valid_range(__first1, __last1);

return std::__is_permutation(__first1, __last1, __first2,
				   __gnu_cxx::__ops::__iter_comp_iter(__pred));
    }

#if __cplusplus > 201103L
  template<typename _ForwardIterator1, typename _ForwardIterator2,
	   typename _BinaryPredicate>
    bool
    __is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
		     _ForwardIterator2 __first2, _ForwardIterator2 __last2,
		     _BinaryPredicate __pred)
    {
      using _Cat1
	= typename iterator_traits<_ForwardIterator1>::iterator_category;
      using _Cat2
	= typename iterator_traits<_ForwardIterator2>::iterator_category;
      using _It1_is_RA = is_same<_Cat1, random_access_iterator_tag>;
      using _It2_is_RA = is_same<_Cat2, random_access_iterator_tag>;
      constexpr bool __ra_iters = _It1_is_RA() && _It2_is_RA();
      if (__ra_iters)
	{
	  auto __d1 = std::distance(__first1, __last1);
	  auto __d2 = std::distance(__first2, __last2);
	  if (__d1 != __d2)
	    return false;
	}

// Efficiently compare identical prefixes:  O(N) if sequences
      // have the same elements in the same order.
      for (; __first1 != __last1 && __first2 != __last2;
	  ++__first1, (void)++__first2)
	if (!__pred(__first1, __first2))
	  break;

if (__ra_iters)
	{
	  if (__first1 == __last1)
	    return true;
	}
      else
	{
	  auto __d1 = std::distance(__first1, __last1);
	  auto __d2 = std::distance(__first2, __last2);
	  if (__d1 == 0 && __d2 == 0)
	    return true;
	  if (__d1 != __d2)
	    return false;
	}

for (_ForwardIterator1 __scan = __first1; __scan != __last1; ++__scan)
	{
	  if (__scan != std::__find_if(__first1, __scan,
			__gnu_cxx::__ops::__iter_comp_iter(__pred, __scan)))
	    continue; // We've seen this one before.

auto __matches = std::__count_if(__first2, __last2,
		__gnu_cxx::__ops::__iter_comp_iter(__pred, __scan));
	  if (0 == __matches
	      || std::__count_if(__scan, __last1,
			__gnu_cxx::__ops::__iter_comp_iter(__pred, __scan))
	      != __matches)
	    return false;
	}
      return true;
    }

/**
   *  @brief  Checks whether a permutaion of the second sequence is equal
   *          to the first sequence.
   *  @ingroup non_mutating_algorithms
   *  @param  __first1  Start of first range.
   *  @param  __last1   End of first range.
   *  @param  __first2  Start of second range.
   *  @param  __last2   End of first range.
   *  @return true if there exists a permutation of the elements in the range
   *          [__first2, __last2), beginning with ForwardIterator2 begin,
   *          such that equal(__first1, __last1, begin) returns true;
   *          otherwise, returns false.
  */
  template<typename _ForwardIterator1, typename _ForwardIterator2>
    inline bool
    is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
		   _ForwardIterator2 __first2, _ForwardIterator2 __last2)
    {
      __glibcxx_requires_valid_range(__first1, __last1);
      __glibcxx_requires_valid_range(__first2, __last2);

return
	std::__is_permutation(__first1, __last1, __first2, __last2,
			      __gnu_cxx::__ops::__iter_equal_to_iter());
    }

/**
   *  @brief  Checks whether a permutation of the second sequence is equal
   *          to the first sequence.
   *  @ingroup non_mutating_algorithms
   *  @param  __first1  Start of first range.
   *  @param  __last1   End of first range.
   *  @param  __first2  Start of second range.
   *  @param  __last2   End of first range.
   *  @param  __pred    A binary predicate.
   *  @return true if there exists a permutation of the elements in the range
   *          [__first2, __last2), beginning with ForwardIterator2 begin,
   *          such that equal(__first1, __last1, __begin, __pred) returns true;
   *          otherwise, returns false.
  */
  template<typename _ForwardIterator1, typename _ForwardIterator2,
	   typename _BinaryPredicate>
    inline bool
    is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
		   _ForwardIterator2 __first2, _ForwardIterator2 __last2,
		   _BinaryPredicate __pred)
    {
      __glibcxx_requires_valid_range(__first1, __last1);
      __glibcxx_requires_valid_range(__first2, __last2);

return std::__is_permutation(__first1, __last1, __first2, __last2,
				   __gnu_cxx::__ops::__iter_comp_iter(__pred));
    }

#if __cplusplus > 201402L

#define __cpp_lib_clamp 201603

/**
   *  @brief  Returns the value clamped between lo and hi.
   *  @ingroup sorting_algorithms
   *  @param  __val  A value of arbitrary type.
   *  @param  __lo   A lower limit of arbitrary type.
   *  @param  __hi   An upper limit of arbitrary type.
   *  @return max(__val, __lo) if __val < __hi or min(__val, __hi) otherwise.
   */
  template<typename _Tp>
    constexpr const _Tp&
    clamp(const _Tp& __val, const _Tp& __lo, const _Tp& __hi)
    {
      __glibcxx_assert(!(__hi < __lo));
      return (__val < __lo) ? __lo : (__hi < __val) ? __hi : __val;
    }

/**
   *  @brief  Returns the value clamped between lo and hi.
   *  @ingroup sorting_algorithms
   *  @param  __val   A value of arbitrary type.
   *  @param  __lo    A lower limit of arbitrary type.
   *  @param  __hi    An upper limit of arbitrary type.
   *  @param  __comp  A comparison functor.
   *  @return max(__val, __lo, __comp) if __comp(__val, __hi)
   *	      or min(__val, __hi, __comp) otherwise.
   */
  template<typename _Tp, typename _Compare>
    constexpr const _Tp&
    clamp(const _Tp& __val, const _Tp& __lo, const _Tp& __hi, _Compare __comp)
    {
      __glibcxx_assert(!__comp(__hi, __lo));
      return __comp(__val, __lo) ? __lo : __comp(__hi, __val) ? __hi : __val;
    }
#endif // C++17
#endif // C++14

#ifdef _GLIBCXX_USE_C99_STDINT_TR1
  /**
   *  @brief Generate two uniformly distributed integers using a
   *         single distribution invocation.
   *  @param  __b0    The upper bound for the first integer.
   *  @param  __b1    The upper bound for the second integer.
   *  @param  __g     A UniformRandomBitGenerator.
   *  @return  A pair (i, j) with i and j uniformly distributed
   *           over [0, __b0) and [0, __b1), respectively.
   *
   *  Requires: __b0 * __b1 <= __g.max() - __g.min().
   *
   *  Using uniform_int_distribution with a range that is very
   *  small relative to the range of the generator ends up wasting
   *  potentially expensively generated randomness, since
   *  uniform_int_distribution does not store leftover randomness
   *  between invocations.
   *
   *  If we know we want two integers in ranges that are sufficiently
   *  small, we can compose the ranges, use a single distribution
   *  invocation, and significantly reduce the waste.
  */
  template<typename _IntType, typename _UniformRandomBitGenerator>
    pair<_IntType, _IntType>
    __gen_two_uniform_ints(_IntType __b0, _IntType __b1,
			   _UniformRandomBitGenerator&& __g)
    {
      _IntType __x
	= uniform_int_distribution<_IntType>{0, (__b0 * __b1) - 1}(__g);
      return std::make_pair(__x / __b1, __x % __b1);
    }

/**
   *  @brief Shuffle the elements of a sequence using a uniform random
   *         number generator.
   *  @ingroup mutating_algorithms
   *  @param  __first   A forward iterator.
   *  @param  __last    A forward iterator.
   *  @param  __g       A UniformRandomNumberGenerator (26.5.1.3).
   *  @return  Nothing.
   *
   *  Reorders the elements in the range @p [__first,__last) using @p __g to
   *  provide random numbers.
  */
  template<typename _RandomAccessIterator,
	   typename _UniformRandomNumberGenerator>
    void
    shuffle(_RandomAccessIterator __first, _RandomAccessIterator __last,
	    _UniformRandomNumberGenerator&& __g)
    {
      // concept requirements
      __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
	    _RandomAccessIterator>)
      __glibcxx_requires_valid_range(__first, __last);

if (__first == __last)
	return;

typedef typename iterator_traits<_RandomAccessIterator>::difference_type
	_DistanceType;

typedef typename std::make_unsigned<_DistanceType>::type __ud_type;
      typedef typename std::uniform_int_distribution<__ud_type> __distr_type;
      typedef typename __distr_type::param_type __p_type;

typedef typename remove_reference<_UniformRandomNumberGenerator>::type
	_Gen;
      typedef typename common_type<typename _Gen::result_type, __ud_type>::type
	__uc_type;

const __uc_type __urngrange = __g.max() - __g.min();
      const __uc_type __urange = __uc_type(__last - __first);

if (__urngrange / __urange >= __urange)
        // I.e. (__urngrange >= __urange * __urange) but without wrap issues.
      {
	_RandomAccessIterator __i = __first + 1;

// Since we know the range isn't empty, an even number of elements
	// means an uneven number of elements /to swap/, in which case we
	// do the first one up front:

if ((__urange % 2) == 0)
	{
	  __distr_type __d{0, 1};
	  std::iter_swap(__i++, __first + __d(__g));
	}

// Now we know that __last - __i is even, so we do the rest in pairs,
	// using a single distribution invocation to produce swap positions
	// for two successive elements at a time:

while (__i != __last)
	{
	  const __uc_type __swap_range = __uc_type(__i - __first) + 1;

const pair<__uc_type, __uc_type> __pospos =
	    __gen_two_uniform_ints(__swap_range, __swap_range + 1, __g);

std::iter_swap(__i++, __first + __pospos.first);
	  std::iter_swap(__i++, __first + __pospos.second);
	}

return;
      }

__distr_type __d;

for (_RandomAccessIterator __i = __first + 1; __i != __last; ++__i)
	std::iter_swap(__i, __first + __d(__g, __p_type(0, __i - __first)));
    }
#endif

#endif // C++11

_GLIBCXX_BEGIN_NAMESPACE_ALGO

/**
   *  @brief Apply a function to every element of a sequence.
   *  @ingroup non_mutating_algorithms
   *  @param  __first  An input iterator.
   *  @param  __last   An input iterator.
   *  @param  __f      A unary function object.
   *  @return   @p __f
   *
   *  Applies the function object @p __f to each element in the range
   *  @p [first,last).  @p __f must not modify the order of the sequence.
   *  If @p __f has a return value it is ignored.
  */
  template<typename _InputIterator, typename _Function>
    _Function
    for_each(_InputIterator __first, _InputIterator __last, _Function __f)
    {
      // concept requirements
      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
      __glibcxx_requires_valid_range(__first, __last);
      for (; __first != __last; ++__first)
	__f(*__first);
      return __f; // N.B. [alg.foreach] says std::move(f) but it's redundant.
    }

/**
   *  @brief Find the first occurrence of a value in a sequence.
   *  @ingroup non_mutating_algorithms
   *  @param  __first  An input iterator.
   *  @param  __last   An input iterator.
   *  @param  __val    The value to find.
   *  @return   The first iterator @c i in the range @p [__first,__last)
   *  such that @c *i == @p __val, or @p __last if no such iterator exists.
  */
  template<typename _InputIterator, typename _Tp>
    inline _InputIterator
    find(_InputIterator __first, _InputIterator __last,
	 const _Tp& __val)
    {
      // concept requirements
      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
      __glibcxx_function_requires(_EqualOpConcept<
		typename iterator_traits<_InputIterator>::value_type, _Tp>)
      __glibcxx_requires_valid_range(__first, __last);
      return std::__find_if(__first, __last,
			    __gnu_cxx::__ops::__iter_equals_val(__val));
    }

/**
   *  @brief Find the first element in a sequence for which a
   *         predicate is true.
   *  @ingroup non_mutating_algorithms
   *  @param  __first  An input iterator.
   *  @param  __last   An input iterator.
   *  @param  __pred   A predicate.
   *  @return   The first iterator @c i in the range @p [__first,__last)
   *  such that @p __pred(*i) is true, or @p __last if no such iterator exists.
  */
  template<typename _InputIterator, typename _Predicate>
    inline _InputIterator
    find_if(_InputIterator __first, _InputIterator __last,
	    _Predicate __pred)
    {
      // concept requirements
      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
      __glibcxx_function_requires(_UnaryPredicateConcept<_Predicate,
	      typename iterator_traits<_InputIterator>::value_type>)
      __glibcxx_requires_valid_range(__first, __last);

return std::__find_if(__first, __last,
			    __gnu_cxx::__ops::__pred_iter(__pred));
    }

/**
   *  @brief  Find element from a set in a sequence.
   *  @ingroup non_mutating_algorithms
   *  @param  __first1  Start of range to search.
   *  @param  __last1   End of range to search.
   *  @param  __first2  Start of match candidates.
   *  @param  __last2   End of match candidates.
   *  @return   The first iterator @c i in the range
   *  @p [__first1,__last1) such that @c *i == @p *(i2) such that i2 is an
   *  iterator in [__first2,__last2), or @p __last1 if no such iterator exists.
   *
   *  Searches the range @p [__first1,__last1) for an element that is
   *  equal to some element in the range [__first2,__last2).  If
   *  found, returns an iterator in the range [__first1,__last1),
   *  otherwise returns @p __last1.
  */
  template<typename _InputIterator, typename _ForwardIterator>
    _InputIterator
    find_first_of(_InputIterator __first1, _InputIterator __last1,
		  _ForwardIterator __first2, _ForwardIterator __last2)
    {
      // concept requirements
      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
      __glibcxx_function_requires(_EqualOpConcept<
	    typename iterator_traits<_InputIterator>::value_type,
	    typename iterator_traits<_ForwardIterator>::value_type>)
      __glibcxx_requires_valid_range(__first1, __last1);
      __glibcxx_requires_valid_range(__first2, __last2);

for (; __first1 != __last1; ++__first1)
	for (_ForwardIterator __iter = __first2; __iter != __last2; ++__iter)
	  if (*__first1 == *__iter)
	    return __first1;
      return __last1;
    }

/**
   *  @brief  Find element from a set in a sequence using a predicate.
   *  @ingroup non_mutating_algorithms
   *  @param  __first1  Start of range to search.
   *  @param  __last1   End of range to search.
   *  @param  __first2  Start of match candidates.
   *  @param  __last2   End of match candidates.
   *  @param  __comp    Predicate to use.
   *  @return   The first iterator @c i in the range
   *  @p [__first1,__last1) such that @c comp(*i, @p *(i2)) is true
   *  and i2 is an iterator in [__first2,__last2), or @p __last1 if no
   *  such iterator exists.
   *

*  Searches the range @p [__first1,__last1) for an element that is
   *  equal to some element in the range [__first2,__last2).  If
   *  found, returns an iterator in the range [__first1,__last1),
   *  otherwise returns @p __last1.
  */
  template<typename _InputIterator, typename _ForwardIterator,
	   typename _BinaryPredicate>
    _InputIterator
    find_first_of(_InputIterator __first1, _InputIterator __last1,
		  _ForwardIterator __first2, _ForwardIterator __last2,
		  _BinaryPredicate __comp)
    {
      // concept requirements
      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
      __glibcxx_function_requires(_BinaryPredicateConcept<_BinaryPredicate,
	    typename iterator_traits<_InputIterator>::value_type,
	    typename iterator_traits<_ForwardIterator>::value_type>)
      __glibcxx_requires_valid_range(__first1, __last1);
      __glibcxx_requires_valid_range(__first2, __last2);

for (; __first1 != __last1; ++__first1)
	for (_ForwardIterator __iter = __first2; __iter != __last2; ++__iter)
	  if (__comp(*__first1, *__iter))
	    return __first1;
      return __last1;
    }

/**
   *  @brief Find two adjacent values in a sequence that are equal.
   *  @ingroup non_mutating_algorithms
   *  @param  __first  A forward iterator.
   *  @param  __last   A forward iterator.
   *  @return   The first iterator @c i such that @c i and @c i+1 are both
   *  valid iterators in @p [__first,__last) and such that @c *i == @c *(i+1),
   *  or @p __last if no such iterator exists.
  */
  template<typename _ForwardIterator>
    inline _ForwardIterator
    adjacent_find(_ForwardIterator __first, _ForwardIterator __last)
    {
      // concept requirements
      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
      __glibcxx_function_requires(_EqualityComparableConcept<
	    typename iterator_traits<_ForwardIterator>::value_type>)
      __glibcxx_requires_valid_range(__first, __last);

return std::__adjacent_find(__first, __last,
				  __gnu_cxx::__ops::__iter_equal_to_iter());
    }

/**
   *  @brief Find two adjacent values in a sequence using a predicate.
   *  @ingroup non_mutating_algorithms
   *  @param  __first         A forward iterator.
   *  @param  __last          A forward iterator.
   *  @param  __binary_pred   A binary predicate.
   *  @return   The first iterator @c i such that @c i and @c i+1 are both
   *  valid iterators in @p [__first,__last) and such that
   *  @p __binary_pred(*i,*(i+1)) is true, or @p __last if no such iterator
   *  exists.
  */
  template<typename _ForwardIterator, typename _BinaryPredicate>
    inline _ForwardIterator
    adjacent_find(_ForwardIterator __first, _ForwardIterator __last,
		  _BinaryPredicate __binary_pred)
    {
      // concept requirements
      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
      __glibcxx_function_requires(_BinaryPredicateConcept<_BinaryPredicate,
	    typename iterator_traits<_ForwardIterator>::value_type,
	    typename iterator_traits<_ForwardIterator>::value_type>)
      __glibcxx_requires_valid_range(__first, __last);

return std::__adjacent_find(__first, __last,
			__gnu_cxx::__ops::__iter_comp_iter(__binary_pred));
    }

/**
   *  @brief Count the number of copies of a value in a sequence.
   *  @ingroup non_mutating_algorithms
   *  @param  __first  An input iterator.
   *  @param  __last   An input iterator.
   *  @param  __value  The value to be counted.
   *  @return   The number of iterators @c i in the range @p [__first,__last)
   *  for which @c *i == @p __value
  */
  template<typename _InputIterator, typename _Tp>
    inline typename iterator_traits<_InputIterator>::difference_type
    count(_InputIterator __first, _InputIterator __last, const _Tp& __value)
    {
      // concept requirements
      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
      __glibcxx_function_requires(_EqualOpConcept<
	    typename iterator_traits<_InputIterator>::value_type, _Tp>)
      __glibcxx_requires_valid_range(__first, __last);

return std::__count_if(__first, __last,
			     __gnu_cxx::__ops::__iter_equals_val(__value));
    }

/**
   *  @brief Count the elements of a sequence for which a predicate is true.
   *  @ingroup non_mutating_algorithms
   *  @param  __first  An input iterator.
   *  @param  __last   An input iterator.
   *  @param  __pred   A predicate.
   *  @return   The number of iterators @c i in the range @p [__first,__last)
   *  for which @p __pred(*i) is true.
  */
  template<typename _InputIterator, typename _Predicate>
    inline typename iterator_traits<_InputIterator>::difference_type
    count_if(_InputIterator __first, _InputIterator __last, _Predicate __pred)
    {
      // concept requirements
      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
      __glibcxx_function_requires(_UnaryPredicateConcept<_Predicate,
	    typename iterator_traits<_InputIterator>::value_type>)
      __glibcxx_requires_valid_range(__first, __last);

return std::__count_if(__first, __last,
			     __gnu_cxx::__ops::__pred_iter(__pred));
    }

/**
   *  @brief Search a sequence for a matching sub-sequence.
   *  @ingroup non_mutating_algorithms
   *  @param  __first1  A forward iterator.
   *  @param  __last1   A forward iterator.
   *  @param  __first2  A forward iterator.
   *  @param  __last2   A forward iterator.
   *  @return The first iterator @c i in the range @p
   *  [__first1,__last1-(__last2-__first2)) such that @c *(i+N) == @p
   *  *(__first2+N) for each @c N in the range @p
   *  [0,__last2-__first2), or @p __last1 if no such iterator exists.
   *
   *  Searches the range @p [__first1,__last1) for a sub-sequence that
   *  compares equal value-by-value with the sequence given by @p
   *  [__first2,__last2) and returns an iterator to the first element
   *  of the sub-sequence, or @p __last1 if the sub-sequence is not
   *  found.
   *
   *  Because the sub-sequence must lie completely within the range @p
   *  [__first1,__last1) it must start at a position less than @p
   *  __last1-(__last2-__first2) where @p __last2-__first2 is the
   *  length of the sub-sequence.
   *
   *  This means that the returned iterator @c i will be in the range
   *  @p [__first1,__last1-(__last2-__first2))
  */
  template<typename _ForwardIterator1, typename _ForwardIterator2>
    inline _ForwardIterator1
    search(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
	   _ForwardIterator2 __first2, _ForwardIterator2 __last2)
    {
      // concept requirements
      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator1>)
      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator2>)
      __glibcxx_function_requires(_EqualOpConcept<
	    typename iterator_traits<_ForwardIterator1>::value_type,
	    typename iterator_traits<_ForwardIterator2>::value_type>)
      __glibcxx_requires_valid_range(__first1, __last1);
      __glibcxx_requires_valid_range(__first2, __last2);

return std::__search(__first1, __last1, __first2, __last2,
			   __gnu_cxx::__ops::__iter_equal_to_iter());
    }

/**
   *  @brief Search a sequence for a matching sub-sequence using a predicate.
   *  @ingroup non_mutating_algorithms
   *  @param  __first1     A forward iterator.
   *  @param  __last1      A forward iterator.
   *  @param  __first2     A forward iterator.
   *  @param  __last2      A forward iterator.
   *  @param  __predicate  A binary predicate.
   *  @return   The first iterator @c i in the range
   *  @p [__first1,__last1-(__last2-__first2)) such that
   *  @p __predicate(*(i+N),*(__first2+N)) is true for each @c N in the range
   *  @p [0,__last2-__first2), or @p __last1 if no such iterator exists.
   *
   *  Searches the range @p [__first1,__last1) for a sub-sequence that
   *  compares equal value-by-value with the sequence given by @p
   *  [__first2,__last2), using @p __predicate to determine equality,
   *  and returns an iterator to the first element of the
   *  sub-sequence, or @p __last1 if no such iterator exists.
   *
   *  @see search(_ForwardIter1, _ForwardIter1, _ForwardIter2, _ForwardIter2)
  */
  template<typename _ForwardIterator1, typename _ForwardIterator2,
	   typename _BinaryPredicate>
    inline _ForwardIterator1
    search(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
	   _ForwardIterator2 __first2, _ForwardIterator2 __last2,
	   _BinaryPredicate  __predicate)
    {
      // concept requirements
      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator1>)
      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator2>)
      __glibcxx_function_requires(_BinaryPredicateConcept<_BinaryPredicate,
	    typename iterator_traits<_ForwardIterator1>::value_type,
	    typename iterator_traits<_ForwardIterator2>::value_type>)
      __glibcxx_requires_valid_range(__first1, __last1);
      __glibcxx_requires_valid_range(__first2, __last2);

return std::__search(__first1, __last1, __first2, __last2,
			   __gnu_cxx::__ops::__iter_comp_iter(__predicate));
    }

/**
   *  @brief Search a sequence for a number of consecutive values.
   *  @ingroup non_mutating_algorithms
   *  @param  __first  A forward iterator.
   *  @param  __last   A forward iterator.
   *  @param  __count  The number of consecutive values.
   *  @param  __val    The value to find.
   *  @return The first iterator @c i in the range @p
   *  [__first,__last-__count) such that @c *(i+N) == @p __val for
   *  each @c N in the range @p [0,__count), or @p __last if no such
   *  iterator exists.
   *
   *  Searches the range @p [__first,__last) for @p count consecutive elements
   *  equal to @p __val.
  */
  template<typename _ForwardIterator, typename _Integer, typename _Tp>
    inline _ForwardIterator
    search_n(_ForwardIterator __first, _ForwardIterator __last,
	     _Integer __count, const _Tp& __val)
    {
      // concept requirements
      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
      __glibcxx_function_requires(_EqualOpConcept<
	    typename iterator_traits<_ForwardIterator>::value_type, _Tp>)
      __glibcxx_requires_valid_range(__first, __last);

return std::__search_n(__first, __last, __count,
			     __gnu_cxx::__ops::__iter_equals_val(__val));
    }

/**
   *  @brief Search a sequence for a number of consecutive values using a
   *         predicate.
   *  @ingroup non_mutating_algorithms
   *  @param  __first        A forward iterator.
   *  @param  __last         A forward iterator.
   *  @param  __count        The number of consecutive values.
   *  @param  __val          The value to find.
   *  @param  __binary_pred  A binary predicate.
   *  @return The first iterator @c i in the range @p
   *  [__first,__last-__count) such that @p
   *  __binary_pred(*(i+N),__val) is true for each @c N in the range
   *  @p [0,__count), or @p __last if no such iterator exists.
   *
   *  Searches the range @p [__first,__last) for @p __count
   *  consecutive elements for which the predicate returns true.
  */
  template<typename _ForwardIterator, typename _Integer, typename _Tp,
	   typename _BinaryPredicate>
    inline _ForwardIterator
    search_n(_ForwardIterator __first, _ForwardIterator __last,
	     _Integer __count, const _Tp& __val,
	     _BinaryPredicate __binary_pred)
    {
      // concept requirements
      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
      __glibcxx_function_requires(_BinaryPredicateConcept<_BinaryPredicate,
	    typename iterator_traits<_ForwardIterator>::value_type, _Tp>)
      __glibcxx_requires_valid_range(__first, __last);

return std::__search_n(__first, __last, __count,
		__gnu_cxx::__ops::__iter_comp_val(__binary_pred, __val));
    }

#if __cplusplus > 201402L
  /** @brief Search a sequence using a Searcher object.
   *
   *  @param  __first        A forward iterator.
   *  @param  __last         A forward iterator.
   *  @param  __searcher     A callable object.
   *  @return @p __searcher(__first,__last).first
  */
  template<typename _ForwardIterator, typename _Searcher>
    inline _ForwardIterator
    search(_ForwardIterator __first, _ForwardIterator __last,
	   const _Searcher& __searcher)
    { return __searcher(__first, __last).first; }
#endif

/**
   *  @brief Perform an operation on a sequence.
   *  @ingroup mutating_algorithms
   *  @param  __first     An input iterator.
   *  @param  __last      An input iterator.
   *  @param  __result    An output iterator.
   *  @param  __unary_op  A unary operator.
   *  @return   An output iterator equal to @p __result+(__last-__first).
   *
   *  Applies the operator to each element in the input range and assigns
   *  the results to successive elements of the output sequence.
   *  Evaluates @p *(__result+N)=unary_op(*(__first+N)) for each @c N in the
   *  range @p [0,__last-__first).
   *
   *  @p unary_op must not alter its argument.
  */
  template<typename _InputIterator, typename _OutputIterator,
	   typename _UnaryOperation>
    _OutputIterator
    transform(_InputIterator __first, _InputIterator __last,
	      _OutputIterator __result, _UnaryOperation __unary_op)
    {
      // concept requirements
      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
	    // "the type returned by a _UnaryOperation"
	    __typeof__(__unary_op(*__first))>)
      __glibcxx_requires_valid_range(__first, __last);

for (; __first != __last; ++__first, (void)++__result)
	*__result = __unary_op(*__first);
      return __result;
    }

/**
   *  @brief Perform an operation on corresponding elements of two sequences.
   *  @ingroup mutating_algorithms
   *  @param  __first1     An input iterator.
   *  @param  __last1      An input iterator.
   *  @param  __first2     An input iterator.
   *  @param  __result     An output iterator.
   *  @param  __binary_op  A binary operator.
   *  @return   An output iterator equal to @p result+(last-first).
   *
   *  Applies the operator to the corresponding elements in the two
   *  input ranges and assigns the results to successive elements of the
   *  output sequence.
   *  Evaluates @p
   *  *(__result+N)=__binary_op(*(__first1+N),*(__first2+N)) for each
   *  @c N in the range @p [0,__last1-__first1).
   *
   *  @p binary_op must not alter either of its arguments.
  */
  template<typename _InputIterator1, typename _InputIterator2,
	   typename _OutputIterator, typename _BinaryOperation>
    _OutputIterator
    transform(_InputIterator1 __first1, _InputIterator1 __last1,
	      _InputIterator2 __first2, _OutputIterator __result,
	      _BinaryOperation __binary_op)
    {
      // concept requirements
      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
	    // "the type returned by a _BinaryOperation"
	    __typeof__(__binary_op(*__first1,*__first2))>)
      __glibcxx_requires_valid_range(__first1, __last1);

for (; __first1 != __last1; ++__first1, (void)++__first2, ++__result)
	*__result = __binary_op(*__first1, *__first2);
      return __result;
    }

/**
   *  @brief Replace each occurrence of one value in a sequence with another
   *         value.
   *  @ingroup mutating_algorithms
   *  @param  __first      A forward iterator.
   *  @param  __last       A forward iterator.
   *  @param  __old_value  The value to be replaced.
   *  @param  __new_value  The replacement value.
   *  @return   replace() returns no value.
   *
   *  For each iterator @c i in the range @p [__first,__last) if @c *i ==
   *  @p __old_value then the assignment @c *i = @p __new_value is performed.
  */
  template<typename _ForwardIterator, typename _Tp>
    void
    replace(_ForwardIterator __first, _ForwardIterator __last,
	    const _Tp& __old_value, const _Tp& __new_value)
    {
      // concept requirements
      __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
				  _ForwardIterator>)
      __glibcxx_function_requires(_EqualOpConcept<
	    typename iterator_traits<_ForwardIterator>::value_type, _Tp>)
      __glibcxx_function_requires(_ConvertibleConcept<_Tp,
	    typename iterator_traits<_ForwardIterator>::value_type>)
      __glibcxx_requires_valid_range(__first, __last);

for (; __first != __last; ++__first)
	if (*__first == __old_value)
	  *__first = __new_value;
    }

/**
   *  @brief Replace each value in a sequence for which a predicate returns
   *         true with another value.
   *  @ingroup mutating_algorithms
   *  @param  __first      A forward iterator.
   *  @param  __last       A forward iterator.
   *  @param  __pred       A predicate.
   *  @param  __new_value  The replacement value.
   *  @return   replace_if() returns no value.
   *
   *  For each iterator @c i in the range @p [__first,__last) if @p __pred(*i)
   *  is true then the assignment @c *i = @p __new_value is performed.
  */
  template<typename _ForwardIterator, typename _Predicate, typename _Tp>
    void
    replace_if(_ForwardIterator __first, _ForwardIterator __last,
	       _Predicate __pred, const _Tp& __new_value)
    {
      // concept requirements
      __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
				  _ForwardIterator>)
      __glibcxx_function_requires(_ConvertibleConcept<_Tp,
	    typename iterator_traits<_ForwardIterator>::value_type>)
      __glibcxx_function_requires(_UnaryPredicateConcept<_Predicate,
	    typename iterator_traits<_ForwardIterator>::value_type>)
      __glibcxx_requires_valid_range(__first, __last);

for (; __first != __last; ++__first)
	if (__pred(*__first))
	  *__first = __new_value;
    }

/**
   *  @brief Assign the result of a function object to each value in a
   *         sequence.
   *  @ingroup mutating_algorithms
   *  @param  __first  A forward iterator.
   *  @param  __last   A forward iterator.
   *  @param  __gen    A function object taking no arguments and returning
   *                 std::iterator_traits<_ForwardIterator>::value_type
   *  @return   generate() returns no value.
   *
   *  Performs the assignment @c *i = @p __gen() for each @c i in the range
   *  @p [__first,__last).
  */
  template<typename _ForwardIterator, typename _Generator>
    void
    generate(_ForwardIterator __first, _ForwardIterator __last,
	     _Generator __gen)
    {
      // concept requirements
      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
      __glibcxx_function_requires(_GeneratorConcept<_Generator,
	    typename iterator_traits<_ForwardIterator>::value_type>)
      __glibcxx_requires_valid_range(__first, __last);

for (; __first != __last; ++__first)
	*__first = __gen();
    }

/**
   *  @brief Assign the result of a function object to each value in a
   *         sequence.
   *  @ingroup mutating_algorithms
   *  @param  __first  A forward iterator.
   *  @param  __n      The length of the sequence.
   *  @param  __gen    A function object taking no arguments and returning
   *                 std::iterator_traits<_ForwardIterator>::value_type
   *  @return   The end of the sequence, @p __first+__n
   *
   *  Performs the assignment @c *i = @p __gen() for each @c i in the range
   *  @p [__first,__first+__n).
   *
   *  _GLIBCXX_RESOLVE_LIB_DEFECTS
   *  DR 865. More algorithms that throw away information
  */
  template<typename _OutputIterator, typename _Size, typename _Generator>
    _OutputIterator
    generate_n(_OutputIterator __first, _Size __n, _Generator __gen)
    {
      // concept requirements
      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
	    // "the type returned by a _Generator"
	    __typeof__(__gen())>)

for (__decltype(__n + 0) __niter = __n;
	   __niter > 0; --__niter, (void) ++__first)
	*__first = __gen();
      return __first;
    }

/**
   *  @brief Copy a sequence, removing consecutive duplicate values.
   *  @ingroup mutating_algorithms
   *  @param  __first   An input iterator.
   *  @param  __last    An input iterator.
   *  @param  __result  An output iterator.
   *  @return   An iterator designating the end of the resulting sequence.
   *
   *  Copies each element in the range @p [__first,__last) to the range
   *  beginning at @p __result, except that only the first element is copied
   *  from groups of consecutive elements that compare equal.
   *  unique_copy() is stable, so the relative order of elements that are
   *  copied is unchanged.
   *
   *  _GLIBCXX_RESOLVE_LIB_DEFECTS
   *  DR 241. Does unique_copy() require CopyConstructible and Assignable?
   *  
   *  _GLIBCXX_RESOLVE_LIB_DEFECTS
   *  DR 538. 241 again: Does unique_copy() require CopyConstructible and 
   *  Assignable?
  */
  template<typename _InputIterator, typename _OutputIterator>
    inline _OutputIterator
    unique_copy(_InputIterator __first, _InputIterator __last,
		_OutputIterator __result)
    {
      // concept requirements
      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
	    typename iterator_traits<_InputIterator>::value_type>)
      __glibcxx_function_requires(_EqualityComparableConcept<
	    typename iterator_traits<_InputIterator>::value_type>)
      __glibcxx_requires_valid_range(__first, __last);

if (__first == __last)
	return __result;
      return std::__unique_copy(__first, __last, __result,
				__gnu_cxx::__ops::__iter_equal_to_iter(),
				std::__iterator_category(__first),
				std::__iterator_category(__result));
    }

/**
   *  @brief Copy a sequence, removing consecutive values using a predicate.
   *  @ingroup mutating_algorithms
   *  @param  __first        An input iterator.
   *  @param  __last         An input iterator.
   *  @param  __result       An output iterator.
   *  @param  __binary_pred  A binary predicate.
   *  @return   An iterator designating the end of the resulting sequence.
   *
   *  Copies each element in the range @p [__first,__last) to the range
   *  beginning at @p __result, except that only the first element is copied
   *  from groups of consecutive elements for which @p __binary_pred returns
   *  true.
   *  unique_copy() is stable, so the relative order of elements that are
   *  copied is unchanged.
   *
   *  _GLIBCXX_RESOLVE_LIB_DEFECTS
   *  DR 241. Does unique_copy() require CopyConstructible and Assignable?
  */
  template<typename _InputIterator, typename _OutputIterator,
	   typename _BinaryPredicate>
    inline _OutputIterator
    unique_copy(_InputIterator __first, _InputIterator __last,
		_OutputIterator __result,
		_BinaryPredicate __binary_pred)
    {
      // concept requirements -- predicates checked later
      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
	    typename iterator_traits<_InputIterator>::value_type>)
      __glibcxx_requires_valid_range(__first, __last);

if (__first == __last)
	return __result;
      return std::__unique_copy(__first, __last, __result,
			__gnu_cxx::__ops::__iter_comp_iter(__binary_pred),
				std::__iterator_category(__first),
				std::__iterator_category(__result));
    }

#if _GLIBCXX_HOSTED
  /**
   *  @brief Randomly shuffle the elements of a sequence.
   *  @ingroup mutating_algorithms
   *  @param  __first   A forward iterator.
   *  @param  __last    A forward iterator.
   *  @return  Nothing.
   *
   *  Reorder the elements in the range @p [__first,__last) using a random
   *  distribution, so that every possible ordering of the sequence is
   *  equally likely.
  */
  template<typename _RandomAccessIterator>
    inline void
    random_shuffle(_RandomAccessIterator __first, _RandomAccessIterator __last)
    {
      // concept requirements
      __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
	    _RandomAccessIterator>)
      __glibcxx_requires_valid_range(__first, __last);

if (__first != __last)
	for (_RandomAccessIterator __i = __first + 1; __i != __last; ++__i)
	  {
	    // XXX rand() % N is not uniformly distributed
	    _RandomAccessIterator __j = __first
					+ std::rand() % ((__i - __first) + 1);
	    if (__i != __j)
	      std::iter_swap(__i, __j);
	  }
    }
#endif

/**
   *  @brief Shuffle the elements of a sequence using a random number
   *         generator.
   *  @ingroup mutating_algorithms
   *  @param  __first   A forward iterator.
   *  @param  __last    A forward iterator.
   *  @param  __rand    The RNG functor or function.
   *  @return  Nothing.
   *
   *  Reorders the elements in the range @p [__first,__last) using @p __rand to
   *  provide a random distribution. Calling @p __rand(N) for a positive
   *  integer @p N should return a randomly chosen integer from the
   *  range [0,N).
  */
  template<typename _RandomAccessIterator, typename _RandomNumberGenerator>
    void
    random_shuffle(_RandomAccessIterator __first, _RandomAccessIterator __last,
#if __cplusplus >= 201103L
		   _RandomNumberGenerator&& __rand)
#else
		   _RandomNumberGenerator& __rand)
#endif
    {
      // concept requirements
      __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
	    _RandomAccessIterator>)
      __glibcxx_requires_valid_range(__first, __last);

if (__first == __last)
	return;
      for (_RandomAccessIterator __i = __first + 1; __i != __last; ++__i)
	{
	  _RandomAccessIterator __j = __first + __rand((__i - __first) + 1);
	  if (__i != __j)
	    std::iter_swap(__i, __j);
	}
    }

/**
   *  @brief Move elements for which a predicate is true to the beginning
   *         of a sequence.
   *  @ingroup mutating_algorithms
   *  @param  __first   A forward iterator.
   *  @param  __last    A forward iterator.
   *  @param  __pred    A predicate functor.
   *  @return  An iterator @p middle such that @p __pred(i) is true for each
   *  iterator @p i in the range @p [__first,middle) and false for each @p i
   *  in the range @p [middle,__last).
   *
   *  @p __pred must not modify its operand. @p partition() does not preserve
   *  the relative ordering of elements in each group, use
   *  @p stable_partition() if this is needed.
  */
  template<typename _ForwardIterator, typename _Predicate>
    inline _ForwardIterator
    partition(_ForwardIterator __first, _ForwardIterator __last,
	      _Predicate   __pred)
    {
      // concept requirements
      __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
				  _ForwardIterator>)
      __glibcxx_function_requires(_UnaryPredicateConcept<_Predicate,
	    typename iterator_traits<_ForwardIterator>::value_type>)
      __glibcxx_requires_valid_range(__first, __last);

return std::__partition(__first, __last, __pred,
			      std::__iterator_category(__first));
    }

/**
   *  @brief Sort the smallest elements of a sequence.
   *  @ingroup sorting_algorithms
   *  @param  __first   An iterator.
   *  @param  __middle  Another iterator.
   *  @param  __last    Another iterator.
   *  @return  Nothing.
   *
   *  Sorts the smallest @p (__middle-__first) elements in the range
   *  @p [first,last) and moves them to the range @p [__first,__middle). The
   *  order of the remaining elements in the range @p [__middle,__last) is
   *  undefined.
   *  After the sort if @e i and @e j are iterators in the range
   *  @p [__first,__middle) such that i precedes j and @e k is an iterator in
   *  the range @p [__middle,__last) then *j<*i and *k<*i are both false.
  */
  template<typename _RandomAccessIterator>
    inline void
    partial_sort(_RandomAccessIterator __first,
		 _RandomAccessIterator __middle,
		 _RandomAccessIterator __last)
    {
      // concept requirements
      __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
	    _RandomAccessIterator>)
      __glibcxx_function_requires(_LessThanComparableConcept<
	    typename iterator_traits<_RandomAccessIterator>::value_type>)
      __glibcxx_requires_valid_range(__first, __middle);
      __glibcxx_requires_valid_range(__middle, __last);
      __glibcxx_requires_irreflexive(__first, __last);

std::__partial_sort(__first, __middle, __last,
			  __gnu_cxx::__ops::__iter_less_iter());
    }

/**
   *  @brief Sort the smallest elements of a sequence using a predicate
   *         for comparison.
   *  @ingroup sorting_algorithms
   *  @param  __first   An iterator.
   *  @param  __middle  Another iterator.
   *  @param  __last    Another iterator.
   *  @param  __comp    A comparison functor.
   *  @return  Nothing.
   *
   *  Sorts the smallest @p (__middle-__first) elements in the range
   *  @p [__first,__last) and moves them to the range @p [__first,__middle). The
   *  order of the remaining elements in the range @p [__middle,__last) is
   *  undefined.
   *  After the sort if @e i and @e j are iterators in the range
   *  @p [__first,__middle) such that i precedes j and @e k is an iterator in
   *  the range @p [__middle,__last) then @p *__comp(j,*i) and @p __comp(*k,*i)
   *  are both false.
  */
  template<typename _RandomAccessIterator, typename _Compare>
    inline void
    partial_sort(_RandomAccessIterator __first,
		 _RandomAccessIterator __middle,
		 _RandomAccessIterator __last,
		 _Compare __comp)
    {
      // concept requirements
      __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
	    _RandomAccessIterator>)
      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
	    typename iterator_traits<_RandomAccessIterator>::value_type,
	    typename iterator_traits<_RandomAccessIterator>::value_type>)
      __glibcxx_requires_valid_range(__first, __middle);
      __glibcxx_requires_valid_range(__middle, __last);
      __glibcxx_requires_irreflexive_pred(__first, __last, __comp);

std::__partial_sort(__first, __middle, __last,
			  __gnu_cxx::__ops::__iter_comp_iter(__comp));
    }

/**
   *  @brief Sort a sequence just enough to find a particular position.
   *  @ingroup sorting_algorithms
   *  @param  __first   An iterator.
   *  @param  __nth     Another iterator.
   *  @param  __last    Another iterator.
   *  @return  Nothing.
   *
   *  Rearranges the elements in the range @p [__first,__last) so that @p *__nth
   *  is the same element that would have been in that position had the
   *  whole sequence been sorted. The elements either side of @p *__nth are
   *  not completely sorted, but for any iterator @e i in the range
   *  @p [__first,__nth) and any iterator @e j in the range @p [__nth,__last) it
   *  holds that *j < *i is false.
  */
  template<typename _RandomAccessIterator>
    inline void
    nth_element(_RandomAccessIterator __first, _RandomAccessIterator __nth,
		_RandomAccessIterator __last)
    {
      // concept requirements
      __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
				  _RandomAccessIterator>)
      __glibcxx_function_requires(_LessThanComparableConcept<
	    typename iterator_traits<_RandomAccessIterator>::value_type>)
      __glibcxx_requires_valid_range(__first, __nth);
      __glibcxx_requires_valid_range(__nth, __last);
      __glibcxx_requires_irreflexive(__first, __last);

if (__first == __last || __nth == __last)
	return;

std::__introselect(__first, __nth, __last,
			 std::__lg(__last - __first) * 2,
			 __gnu_cxx::__ops::__iter_less_iter());
    }

/**
   *  @brief Sort a sequence just enough to find a particular position
   *         using a predicate for comparison.
   *  @ingroup sorting_algorithms
   *  @param  __first   An iterator.
   *  @param  __nth     Another iterator.
   *  @param  __last    Another iterator.
   *  @param  __comp    A comparison functor.
   *  @return  Nothing.
   *
   *  Rearranges the elements in the range @p [__first,__last) so that @p *__nth
   *  is the same element that would have been in that position had the
   *  whole sequence been sorted. The elements either side of @p *__nth are
   *  not completely sorted, but for any iterator @e i in the range
   *  @p [__first,__nth) and any iterator @e j in the range @p [__nth,__last) it
   *  holds that @p __comp(*j,*i) is false.
  */
  template<typename _RandomAccessIterator, typename _Compare>
    inline void
    nth_element(_RandomAccessIterator __first, _RandomAccessIterator __nth,
		_RandomAccessIterator __last, _Compare __comp)
    {
      // concept requirements
      __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
				  _RandomAccessIterator>)
      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
	    typename iterator_traits<_RandomAccessIterator>::value_type,
	    typename iterator_traits<_RandomAccessIterator>::value_type>)
      __glibcxx_requires_valid_range(__first, __nth);
      __glibcxx_requires_valid_range(__nth, __last);
      __glibcxx_requires_irreflexive_pred(__first, __last, __comp);

if (__first == __last || __nth == __last)
	return;

std::__introselect(__first, __nth, __last,
			 std::__lg(__last - __first) * 2,
			 __gnu_cxx::__ops::__iter_comp_iter(__comp));
    }

/**
   *  @brief Sort the elements of a sequence.
   *  @ingroup sorting_algorithms
   *  @param  __first   An iterator.
   *  @param  __last    Another iterator.
   *  @return  Nothing.
   *
   *  Sorts the elements in the range @p [__first,__last) in ascending order,
   *  such that for each iterator @e i in the range @p [__first,__last-1),  
   *  *(i+1)<*i is false.
   *
   *  The relative ordering of equivalent elements is not preserved, use
   *  @p stable_sort() if this is needed.
  */
  template<typename _RandomAccessIterator>
    inline void
    sort(_RandomAccessIterator __first, _RandomAccessIterator __last)
    {
      // concept requirements
      __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
	    _RandomAccessIterator>)
      __glibcxx_function_requires(_LessThanComparableConcept<
	    typename iterator_traits<_RandomAccessIterator>::value_type>)
      __glibcxx_requires_valid_range(__first, __last);
      __glibcxx_requires_irreflexive(__first, __last);

std::__sort(__first, __last, __gnu_cxx::__ops::__iter_less_iter());
    }

/**
   *  @brief Sort the elements of a sequence using a predicate for comparison.
   *  @ingroup sorting_algorithms
   *  @param  __first   An iterator.
   *  @param  __last    Another iterator.
   *  @param  __comp    A comparison functor.
   *  @return  Nothing.
   *
   *  Sorts the elements in the range @p [__first,__last) in ascending order,
   *  such that @p __comp(*(i+1),*i) is false for every iterator @e i in the
   *  range @p [__first,__last-1).
   *
   *  The relative ordering of equivalent elements is not preserved, use
   *  @p stable_sort() if this is needed.
  */
  template<typename _RandomAccessIterator, typename _Compare>
    inline void
    sort(_RandomAccessIterator __first, _RandomAccessIterator __last,
	 _Compare __comp)
    {
      // concept requirements
      __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
	    _RandomAccessIterator>)
      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
	    typename iterator_traits<_RandomAccessIterator>::value_type,
	    typename iterator_traits<_RandomAccessIterator>::value_type>)
      __glibcxx_requires_valid_range(__first, __last);
      __glibcxx_requires_irreflexive_pred(__first, __last, __comp);

std::__sort(__first, __last, __gnu_cxx::__ops::__iter_comp_iter(__comp));
    }

template<typename _InputIterator1, typename _InputIterator2,
	   typename _OutputIterator, typename _Compare>
    _OutputIterator
    __merge(_InputIterator1 __first1, _InputIterator1 __last1,
	    _InputIterator2 __first2, _InputIterator2 __last2,
	    _OutputIterator __result, _Compare __comp)
    {
      while (__first1 != __last1 && __first2 != __last2)
	{
	  if (__comp(__first2, __first1))
	    {
	      *__result = *__first2;
	      ++__first2;
	    }
	  else
	    {
	      *__result = *__first1;
	      ++__first1;
	    }
	  ++__result;
	}
      return std::copy(__first2, __last2,
		       std::copy(__first1, __last1, __result));
    }

/**
   *  @brief Merges two sorted ranges.
   *  @ingroup sorting_algorithms
   *  @param  __first1  An iterator.
   *  @param  __first2  Another iterator.
   *  @param  __last1   Another iterator.
   *  @param  __last2   Another iterator.
   *  @param  __result  An iterator pointing to the end of the merged range.
   *  @return         An iterator pointing to the first element <em>not less
   *                  than</em> @e val.
   *
   *  Merges the ranges @p [__first1,__last1) and @p [__first2,__last2) into
   *  the sorted range @p [__result, __result + (__last1-__first1) +
   *  (__last2-__first2)).  Both input ranges must be sorted, and the
   *  output range must not overlap with either of the input ranges.
   *  The sort is @e stable, that is, for equivalent elements in the
   *  two ranges, elements from the first range will always come
   *  before elements from the second.
  */
  template<typename _InputIterator1, typename _InputIterator2,
	   typename _OutputIterator>
    inline _OutputIterator
    merge(_InputIterator1 __first1, _InputIterator1 __last1,
	  _InputIterator2 __first2, _InputIterator2 __last2,
	  _OutputIterator __result)
    {
      // concept requirements
      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
	    typename iterator_traits<_InputIterator1>::value_type>)
      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
	    typename iterator_traits<_InputIterator2>::value_type>)
      __glibcxx_function_requires(_LessThanOpConcept<
	    typename iterator_traits<_InputIterator2>::value_type,
	    typename iterator_traits<_InputIterator1>::value_type>)	
      __glibcxx_requires_sorted_set(__first1, __last1, __first2);
      __glibcxx_requires_sorted_set(__first2, __last2, __first1);
      __glibcxx_requires_irreflexive2(__first1, __last1);
      __glibcxx_requires_irreflexive2(__first2, __last2);

return _GLIBCXX_STD_A::__merge(__first1, __last1,
				     __first2, __last2, __result,
				     __gnu_cxx::__ops::__iter_less_iter());
    }

/**
   *  @brief Merges two sorted ranges.
   *  @ingroup sorting_algorithms
   *  @param  __first1  An iterator.
   *  @param  __first2  Another iterator.
   *  @param  __last1   Another iterator.
   *  @param  __last2   Another iterator.
   *  @param  __result  An iterator pointing to the end of the merged range.
   *  @param  __comp    A functor to use for comparisons.
   *  @return         An iterator pointing to the first element "not less
   *                  than" @e val.
   *
   *  Merges the ranges @p [__first1,__last1) and @p [__first2,__last2) into
   *  the sorted range @p [__result, __result + (__last1-__first1) +
   *  (__last2-__first2)).  Both input ranges must be sorted, and the
   *  output range must not overlap with either of the input ranges.
   *  The sort is @e stable, that is, for equivalent elements in the
   *  two ranges, elements from the first range will always come
   *  before elements from the second.
   *
   *  The comparison function should have the same effects on ordering as
   *  the function used for the initial sort.
  */
  template<typename _InputIterator1, typename _InputIterator2,
	   typename _OutputIterator, typename _Compare>
    inline _OutputIterator
    merge(_InputIterator1 __first1, _InputIterator1 __last1,
	  _InputIterator2 __first2, _InputIterator2 __last2,
	  _OutputIterator __result, _Compare __comp)
    {
      // concept requirements
      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
	    typename iterator_traits<_InputIterator1>::value_type>)
      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
	    typename iterator_traits<_InputIterator2>::value_type>)
      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
	    typename iterator_traits<_InputIterator2>::value_type,
	    typename iterator_traits<_InputIterator1>::value_type>)
      __glibcxx_requires_sorted_set_pred(__first1, __last1, __first2, __comp);
      __glibcxx_requires_sorted_set_pred(__first2, __last2, __first1, __comp);
      __glibcxx_requires_irreflexive_pred2(__first1, __last1, __comp);
      __glibcxx_requires_irreflexive_pred2(__first2, __last2, __comp);

return _GLIBCXX_STD_A::__merge(__first1, __last1,
				__first2, __last2, __result,
				__gnu_cxx::__ops::__iter_comp_iter(__comp));
    }

template<typename _RandomAccessIterator, typename _Compare>
    inline void
    __stable_sort(_RandomAccessIterator __first, _RandomAccessIterator __last,
		  _Compare __comp)
    {
      typedef typename iterator_traits<_RandomAccessIterator>::value_type
	_ValueType;
      typedef typename iterator_traits<_RandomAccessIterator>::difference_type
	_DistanceType;

typedef _Temporary_buffer<_RandomAccessIterator, _ValueType> _TmpBuf;
      _TmpBuf __buf(__first, __last);

if (__buf.begin() == 0)
	std::__inplace_stable_sort(__first, __last, __comp);
      else
	std::__stable_sort_adaptive(__first, __last, __buf.begin(),
				    _DistanceType(__buf.size()), __comp);
    }

/**
   *  @brief Sort the elements of a sequence, preserving the relative order
   *         of equivalent elements.
   *  @ingroup sorting_algorithms
   *  @param  __first   An iterator.
   *  @param  __last    Another iterator.
   *  @return  Nothing.
   *
   *  Sorts the elements in the range @p [__first,__last) in ascending order,
   *  such that for each iterator @p i in the range @p [__first,__last-1),
   *  @p *(i+1)<*i is false.
   *
   *  The relative ordering of equivalent elements is preserved, so any two
   *  elements @p x and @p y in the range @p [__first,__last) such that
   *  @p x<y is false and @p y<x is false will have the same relative
   *  ordering after calling @p stable_sort().
  */
  template<typename _RandomAccessIterator>
    inline void
    stable_sort(_RandomAccessIterator __first, _RandomAccessIterator __last)
    {
      // concept requirements
      __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
	    _RandomAccessIterator>)
      __glibcxx_function_requires(_LessThanComparableConcept<
	    typename iterator_traits<_RandomAccessIterator>::value_type>)
      __glibcxx_requires_valid_range(__first, __last);
      __glibcxx_requires_irreflexive(__first, __last);

_GLIBCXX_STD_A::__stable_sort(__first, __last,
				    __gnu_cxx::__ops::__iter_less_iter());
    }

/**
   *  @brief Sort the elements of a sequence using a predicate for comparison,
   *         preserving the relative order of equivalent elements.
   *  @ingroup sorting_algorithms
   *  @param  __first   An iterator.
   *  @param  __last    Another iterator.
   *  @param  __comp    A comparison functor.
   *  @return  Nothing.
   *
   *  Sorts the elements in the range @p [__first,__last) in ascending order,
   *  such that for each iterator @p i in the range @p [__first,__last-1),
   *  @p __comp(*(i+1),*i) is false.
   *
   *  The relative ordering of equivalent elements is preserved, so any two
   *  elements @p x and @p y in the range @p [__first,__last) such that
   *  @p __comp(x,y) is false and @p __comp(y,x) is false will have the same
   *  relative ordering after calling @p stable_sort().
  */
  template<typename _RandomAccessIterator, typename _Compare>
    inline void
    stable_sort(_RandomAccessIterator __first, _RandomAccessIterator __last,
		_Compare __comp)
    {
      // concept requirements
      __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
	    _RandomAccessIterator>)
      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
	    typename iterator_traits<_RandomAccessIterator>::value_type,
	    typename iterator_traits<_RandomAccessIterator>::value_type>)
      __glibcxx_requires_valid_range(__first, __last);
      __glibcxx_requires_irreflexive_pred(__first, __last, __comp);

_GLIBCXX_STD_A::__stable_sort(__first, __last,
				    __gnu_cxx::__ops::__iter_comp_iter(__comp));
    }

template<typename _InputIterator1, typename _InputIterator2,
	   typename _OutputIterator,
	   typename _Compare>
    _OutputIterator
    __set_union(_InputIterator1 __first1, _InputIterator1 __last1,
		_InputIterator2 __first2, _InputIterator2 __last2,
		_OutputIterator __result, _Compare __comp)
    {
      while (__first1 != __last1 && __first2 != __last2)
	{
	  if (__comp(__first1, __first2))
	    {
	      *__result = *__first1;
	      ++__first1;
	    }
	  else if (__comp(__first2, __first1))
	    {
	      *__result = *__first2;
	      ++__first2;
	    }
	  else
	    {
	      *__result = *__first1;
	      ++__first1;
	      ++__first2;
	    }
	  ++__result;
	}
      return std::copy(__first2, __last2,
		       std::copy(__first1, __last1, __result));
    }

/**
   *  @brief Return the union of two sorted ranges.
   *  @ingroup set_algorithms
   *  @param  __first1  Start of first range.
   *  @param  __last1   End of first range.
   *  @param  __first2  Start of second range.
   *  @param  __last2   End of second range.
   *  @param  __result  Start of output range.
   *  @return  End of the output range.
   *  @ingroup set_algorithms
   *
   *  This operation iterates over both ranges, copying elements present in
   *  each range in order to the output range.  Iterators increment for each
   *  range.  When the current element of one range is less than the other,
   *  that element is copied and the iterator advanced.  If an element is
   *  contained in both ranges, the element from the first range is copied and
   *  both ranges advance.  The output range may not overlap either input
   *  range.
  */
  template<typename _InputIterator1, typename _InputIterator2,
	   typename _OutputIterator>
    inline _OutputIterator
    set_union(_InputIterator1 __first1, _InputIterator1 __last1,
	      _InputIterator2 __first2, _InputIterator2 __last2,
	      _OutputIterator __result)
    {
      // concept requirements
      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
	    typename iterator_traits<_InputIterator1>::value_type>)
      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
	    typename iterator_traits<_InputIterator2>::value_type>)
      __glibcxx_function_requires(_LessThanOpConcept<
	    typename iterator_traits<_InputIterator1>::value_type,
	    typename iterator_traits<_InputIterator2>::value_type>)
      __glibcxx_function_requires(_LessThanOpConcept<
	    typename iterator_traits<_InputIterator2>::value_type,
	    typename iterator_traits<_InputIterator1>::value_type>)
      __glibcxx_requires_sorted_set(__first1, __last1, __first2);
      __glibcxx_requires_sorted_set(__first2, __last2, __first1);
      __glibcxx_requires_irreflexive2(__first1, __last1);
      __glibcxx_requires_irreflexive2(__first2, __last2);

return _GLIBCXX_STD_A::__set_union(__first1, __last1,
				__first2, __last2, __result,
				__gnu_cxx::__ops::__iter_less_iter());
    }

/**
   *  @brief Return the union of two sorted ranges using a comparison functor.
   *  @ingroup set_algorithms
   *  @param  __first1  Start of first range.
   *  @param  __last1   End of first range.
   *  @param  __first2  Start of second range.
   *  @param  __last2   End of second range.
   *  @param  __result  Start of output range.
   *  @param  __comp    The comparison functor.
   *  @return  End of the output range.
   *  @ingroup set_algorithms
   *
   *  This operation iterates over both ranges, copying elements present in
   *  each range in order to the output range.  Iterators increment for each
   *  range.  When the current element of one range is less than the other
   *  according to @p __comp, that element is copied and the iterator advanced.
   *  If an equivalent element according to @p __comp is contained in both
   *  ranges, the element from the first range is copied and both ranges
   *  advance.  The output range may not overlap either input range.
  */
  template<typename _InputIterator1, typename _InputIterator2,
	   typename _OutputIterator, typename _Compare>
    inline _OutputIterator
    set_union(_InputIterator1 __first1, _InputIterator1 __last1,
	      _InputIterator2 __first2, _InputIterator2 __last2,
	      _OutputIterator __result, _Compare __comp)
    {
      // concept requirements
      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
	    typename iterator_traits<_InputIterator1>::value_type>)
      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
	    typename iterator_traits<_InputIterator2>::value_type>)
      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
	    typename iterator_traits<_InputIterator1>::value_type,
	    typename iterator_traits<_InputIterator2>::value_type>)
      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
	    typename iterator_traits<_InputIterator2>::value_type,
	    typename iterator_traits<_InputIterator1>::value_type>)
      __glibcxx_requires_sorted_set_pred(__first1, __last1, __first2, __comp);
      __glibcxx_requires_sorted_set_pred(__first2, __last2, __first1, __comp);
      __glibcxx_requires_irreflexive_pred2(__first1, __last1, __comp);
      __glibcxx_requires_irreflexive_pred2(__first2, __last2, __comp);

return _GLIBCXX_STD_A::__set_union(__first1, __last1,
				__first2, __last2, __result,
				__gnu_cxx::__ops::__iter_comp_iter(__comp));
    }

template<typename _InputIterator1, typename _InputIterator2,
	   typename _OutputIterator,
	   typename _Compare>
    _OutputIterator
    __set_intersection(_InputIterator1 __first1, _InputIterator1 __last1,
		       _InputIterator2 __first2, _InputIterator2 __last2,
		       _OutputIterator __result, _Compare __comp)
    {
      while (__first1 != __last1 && __first2 != __last2)
	if (__comp(__first1, __first2))
	  ++__first1;
	else if (__comp(__first2, __first1))
	  ++__first2;
	else
	  {
	    *__result = *__first1;
	    ++__first1;
	    ++__first2;
	    ++__result;
	  }
      return __result;
    }

/**
   *  @brief Return the intersection of two sorted ranges.
   *  @ingroup set_algorithms
   *  @param  __first1  Start of first range.
   *  @param  __last1   End of first range.
   *  @param  __first2  Start of second range.
   *  @param  __last2   End of second range.
   *  @param  __result  Start of output range.
   *  @return  End of the output range.
   *  @ingroup set_algorithms
   *
   *  This operation iterates over both ranges, copying elements present in
   *  both ranges in order to the output range.  Iterators increment for each
   *  range.  When the current element of one range is less than the other,
   *  that iterator advances.  If an element is contained in both ranges, the
   *  element from the first range is copied and both ranges advance.  The
   *  output range may not overlap either input range.
  */
  template<typename _InputIterator1, typename _InputIterator2,
	   typename _OutputIterator>
    inline _OutputIterator
    set_intersection(_InputIterator1 __first1, _InputIterator1 __last1,
		     _InputIterator2 __first2, _InputIterator2 __last2,
		     _OutputIterator __result)
    {
      // concept requirements
      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
	    typename iterator_traits<_InputIterator1>::value_type>)
      __glibcxx_function_requires(_LessThanOpConcept<
	    typename iterator_traits<_InputIterator1>::value_type,
	    typename iterator_traits<_InputIterator2>::value_type>)
      __glibcxx_function_requires(_LessThanOpConcept<
	    typename iterator_traits<_InputIterator2>::value_type,
	    typename iterator_traits<_InputIterator1>::value_type>)
      __glibcxx_requires_sorted_set(__first1, __last1, __first2);
      __glibcxx_requires_sorted_set(__first2, __last2, __first1);
      __glibcxx_requires_irreflexive2(__first1, __last1);
      __glibcxx_requires_irreflexive2(__first2, __last2);

return _GLIBCXX_STD_A::__set_intersection(__first1, __last1,
				     __first2, __last2, __result,
				     __gnu_cxx::__ops::__iter_less_iter());
    }

/**
   *  @brief Return the intersection of two sorted ranges using comparison
   *  functor.
   *  @ingroup set_algorithms
   *  @param  __first1  Start of first range.
   *  @param  __last1   End of first range.
   *  @param  __first2  Start of second range.
   *  @param  __last2   End of second range.
   *  @param  __result  Start of output range.
   *  @param  __comp    The comparison functor.
   *  @return  End of the output range.
   *  @ingroup set_algorithms
   *
   *  This operation iterates over both ranges, copying elements present in
   *  both ranges in order to the output range.  Iterators increment for each
   *  range.  When the current element of one range is less than the other
   *  according to @p __comp, that iterator advances.  If an element is
   *  contained in both ranges according to @p __comp, the element from the
   *  first range is copied and both ranges advance.  The output range may not
   *  overlap either input range.
  */
  template<typename _InputIterator1, typename _InputIterator2,
	   typename _OutputIterator, typename _Compare>
    inline _OutputIterator
    set_intersection(_InputIterator1 __first1, _InputIterator1 __last1,
		     _InputIterator2 __first2, _InputIterator2 __last2,
		     _OutputIterator __result, _Compare __comp)
    {
      // concept requirements
      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
	    typename iterator_traits<_InputIterator1>::value_type>)
      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
	    typename iterator_traits<_InputIterator1>::value_type,
	    typename iterator_traits<_InputIterator2>::value_type>)
      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
	    typename iterator_traits<_InputIterator2>::value_type,
	    typename iterator_traits<_InputIterator1>::value_type>)
      __glibcxx_requires_sorted_set_pred(__first1, __last1, __first2, __comp);
      __glibcxx_requires_sorted_set_pred(__first2, __last2, __first1, __comp);
      __glibcxx_requires_irreflexive_pred2(__first1, __last1, __comp);
      __glibcxx_requires_irreflexive_pred2(__first2, __last2, __comp);

return _GLIBCXX_STD_A::__set_intersection(__first1, __last1,
				__first2, __last2, __result,
				__gnu_cxx::__ops::__iter_comp_iter(__comp));
    }

template<typename _InputIterator1, typename _InputIterator2,
	   typename _OutputIterator,
	   typename _Compare>
    _OutputIterator
    __set_difference(_InputIterator1 __first1, _InputIterator1 __last1,
		     _InputIterator2 __first2, _InputIterator2 __last2,
		     _OutputIterator __result, _Compare __comp)
    {
      while (__first1 != __last1 && __first2 != __last2)
	if (__comp(__first1, __first2))
	  {
	    *__result = *__first1;
	    ++__first1;
	    ++__result;
	  }
	else if (__comp(__first2, __first1))
	  ++__first2;
	else
	  {
	    ++__first1;
	    ++__first2;
	  }
      return std::copy(__first1, __last1, __result);
    }

/**
   *  @brief Return the difference of two sorted ranges.
   *  @ingroup set_algorithms
   *  @param  __first1  Start of first range.
   *  @param  __last1   End of first range.
   *  @param  __first2  Start of second range.
   *  @param  __last2   End of second range.
   *  @param  __result  Start of output range.
   *  @return  End of the output range.
   *  @ingroup set_algorithms
   *
   *  This operation iterates over both ranges, copying elements present in
   *  the first range but not the second in order to the output range.
   *  Iterators increment for each range.  When the current element of the
   *  first range is less than the second, that element is copied and the
   *  iterator advances.  If the current element of the second range is less,
   *  the iterator advances, but no element is copied.  If an element is
   *  contained in both ranges, no elements are copied and both ranges
   *  advance.  The output range may not overlap either input range.
  */
  template<typename _InputIterator1, typename _InputIterator2,
	   typename _OutputIterator>
    inline _OutputIterator
    set_difference(_InputIterator1 __first1, _InputIterator1 __last1,
		   _InputIterator2 __first2, _InputIterator2 __last2,
		   _OutputIterator __result)
    {
      // concept requirements
      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
	    typename iterator_traits<_InputIterator1>::value_type>)
      __glibcxx_function_requires(_LessThanOpConcept<
	    typename iterator_traits<_InputIterator1>::value_type,
	    typename iterator_traits<_InputIterator2>::value_type>)
      __glibcxx_function_requires(_LessThanOpConcept<
	    typename iterator_traits<_InputIterator2>::value_type,
	    typename iterator_traits<_InputIterator1>::value_type>)	
      __glibcxx_requires_sorted_set(__first1, __last1, __first2);
      __glibcxx_requires_sorted_set(__first2, __last2, __first1);
      __glibcxx_requires_irreflexive2(__first1, __last1);
      __glibcxx_requires_irreflexive2(__first2, __last2);

return _GLIBCXX_STD_A::__set_difference(__first1, __last1,
				   __first2, __last2, __result,
				   __gnu_cxx::__ops::__iter_less_iter());
    }

/**
   *  @brief  Return the difference of two sorted ranges using comparison
   *  functor.
   *  @ingroup set_algorithms
   *  @param  __first1  Start of first range.
   *  @param  __last1   End of first range.
   *  @param  __first2  Start of second range.
   *  @param  __last2   End of second range.
   *  @param  __result  Start of output range.
   *  @param  __comp    The comparison functor.
   *  @return  End of the output range.
   *  @ingroup set_algorithms
   *
   *  This operation iterates over both ranges, copying elements present in
   *  the first range but not the second in order to the output range.
   *  Iterators increment for each range.  When the current element of the
   *  first range is less than the second according to @p __comp, that element
   *  is copied and the iterator advances.  If the current element of the
   *  second range is less, no element is copied and the iterator advances.
   *  If an element is contained in both ranges according to @p __comp, no
   *  elements are copied and both ranges advance.  The output range may not
   *  overlap either input range.
  */
  template<typename _InputIterator1, typename _InputIterator2,
	   typename _OutputIterator, typename _Compare>
    inline _OutputIterator
    set_difference(_InputIterator1 __first1, _InputIterator1 __last1,
		   _InputIterator2 __first2, _InputIterator2 __last2,
		   _OutputIterator __result, _Compare __comp)
    {
      // concept requirements
      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
	    typename iterator_traits<_InputIterator1>::value_type>)
      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
	    typename iterator_traits<_InputIterator1>::value_type,
	    typename iterator_traits<_InputIterator2>::value_type>)
      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
	    typename iterator_traits<_InputIterator2>::value_type,
	    typename iterator_traits<_InputIterator1>::value_type>)
      __glibcxx_requires_sorted_set_pred(__first1, __last1, __first2, __comp);
      __glibcxx_requires_sorted_set_pred(__first2, __last2, __first1, __comp);
      __glibcxx_requires_irreflexive_pred2(__first1, __last1, __comp);
      __glibcxx_requires_irreflexive_pred2(__first2, __last2, __comp);

return _GLIBCXX_STD_A::__set_difference(__first1, __last1,
				   __first2, __last2, __result,
				   __gnu_cxx::__ops::__iter_comp_iter(__comp));
    }

template<typename _InputIterator1, typename _InputIterator2,
	   typename _OutputIterator,
	   typename _Compare>
    _OutputIterator
    __set_symmetric_difference(_InputIterator1 __first1,
			       _InputIterator1 __last1,
			       _InputIterator2 __first2,
			       _InputIterator2 __last2,
			       _OutputIterator __result,
			       _Compare __comp)
    {
      while (__first1 != __last1 && __first2 != __last2)
	if (__comp(__first1, __first2))
	  {
	    *__result = *__first1;
	    ++__first1;
	    ++__result;
	  }
	else if (__comp(__first2, __first1))
	  {
	    *__result = *__first2;
	    ++__first2;
	    ++__result;
	  }
	else
	  {
	    ++__first1;
	    ++__first2;
	  }
      return std::copy(__first2, __last2, 
		       std::copy(__first1, __last1, __result));
    }

/**
   *  @brief  Return the symmetric difference of two sorted ranges.
   *  @ingroup set_algorithms
   *  @param  __first1  Start of first range.
   *  @param  __last1   End of first range.
   *  @param  __first2  Start of second range.
   *  @param  __last2   End of second range.
   *  @param  __result  Start of output range.
   *  @return  End of the output range.
   *  @ingroup set_algorithms
   *
   *  This operation iterates over both ranges, copying elements present in
   *  one range but not the other in order to the output range.  Iterators
   *  increment for each range.  When the current element of one range is less
   *  than the other, that element is copied and the iterator advances.  If an
   *  element is contained in both ranges, no elements are copied and both
   *  ranges advance.  The output range may not overlap either input range.
  */
  template<typename _InputIterator1, typename _InputIterator2,
	   typename _OutputIterator>
    inline _OutputIterator
    set_symmetric_difference(_InputIterator1 __first1, _InputIterator1 __last1,
			     _InputIterator2 __first2, _InputIterator2 __last2,
			     _OutputIterator __result)
    {
      // concept requirements
      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
	    typename iterator_traits<_InputIterator1>::value_type>)
      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
	    typename iterator_traits<_InputIterator2>::value_type>)
      __glibcxx_function_requires(_LessThanOpConcept<
	    typename iterator_traits<_InputIterator1>::value_type,
	    typename iterator_traits<_InputIterator2>::value_type>)
      __glibcxx_function_requires(_LessThanOpConcept<
	    typename iterator_traits<_InputIterator2>::value_type,
	    typename iterator_traits<_InputIterator1>::value_type>)	
      __glibcxx_requires_sorted_set(__first1, __last1, __first2);
      __glibcxx_requires_sorted_set(__first2, __last2, __first1);
      __glibcxx_requires_irreflexive2(__first1, __last1);
      __glibcxx_requires_irreflexive2(__first2, __last2);

return _GLIBCXX_STD_A::__set_symmetric_difference(__first1, __last1,
					__first2, __last2, __result,
					__gnu_cxx::__ops::__iter_less_iter());
    }

/**
   *  @brief  Return the symmetric difference of two sorted ranges using
   *  comparison functor.
   *  @ingroup set_algorithms
   *  @param  __first1  Start of first range.
   *  @param  __last1   End of first range.
   *  @param  __first2  Start of second range.
   *  @param  __last2   End of second range.
   *  @param  __result  Start of output range.
   *  @param  __comp    The comparison functor.
   *  @return  End of the output range.
   *  @ingroup set_algorithms
   *
   *  This operation iterates over both ranges, copying elements present in
   *  one range but not the other in order to the output range.  Iterators
   *  increment for each range.  When the current element of one range is less
   *  than the other according to @p comp, that element is copied and the
   *  iterator advances.  If an element is contained in both ranges according
   *  to @p __comp, no elements are copied and both ranges advance.  The output
   *  range may not overlap either input range.
  */
  template<typename _InputIterator1, typename _InputIterator2,
	   typename _OutputIterator, typename _Compare>
    inline _OutputIterator
    set_symmetric_difference(_InputIterator1 __first1, _InputIterator1 __last1,
			     _InputIterator2 __first2, _InputIterator2 __last2,
			     _OutputIterator __result,
			     _Compare __comp)
    {
      // concept requirements
      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
	    typename iterator_traits<_InputIterator1>::value_type>)
      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
	    typename iterator_traits<_InputIterator2>::value_type>)
      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
	    typename iterator_traits<_InputIterator1>::value_type,
	    typename iterator_traits<_InputIterator2>::value_type>)
      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
	    typename iterator_traits<_InputIterator2>::value_type,
	    typename iterator_traits<_InputIterator1>::value_type>)
      __glibcxx_requires_sorted_set_pred(__first1, __last1, __first2, __comp);
      __glibcxx_requires_sorted_set_pred(__first2, __last2, __first1, __comp);
      __glibcxx_requires_irreflexive_pred2(__first1, __last1, __comp);
      __glibcxx_requires_irreflexive_pred2(__first2, __last2, __comp);

return _GLIBCXX_STD_A::__set_symmetric_difference(__first1, __last1,
				__first2, __last2, __result,
				__gnu_cxx::__ops::__iter_comp_iter(__comp));
    }

template<typename _ForwardIterator, typename _Compare>
    _GLIBCXX14_CONSTEXPR
    _ForwardIterator
    __min_element(_ForwardIterator __first, _ForwardIterator __last,
		  _Compare __comp)
    {
      if (__first == __last)
	return __first;
      _ForwardIterator __result = __first;
      while (++__first != __last)
	if (__comp(__first, __result))
	  __result = __first;
      return __result;
    }

/**
   *  @brief  Return the minimum element in a range.
   *  @ingroup sorting_algorithms
   *  @param  __first  Start of range.
   *  @param  __last   End of range.
   *  @return  Iterator referencing the first instance of the smallest value.
  */
  template<typename _ForwardIterator>
    _GLIBCXX14_CONSTEXPR
    _ForwardIterator
    inline min_element(_ForwardIterator __first, _ForwardIterator __last)
    {
      // concept requirements
      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
      __glibcxx_function_requires(_LessThanComparableConcept<
	    typename iterator_traits<_ForwardIterator>::value_type>)
      __glibcxx_requires_valid_range(__first, __last);
      __glibcxx_requires_irreflexive(__first, __last);

return _GLIBCXX_STD_A::__min_element(__first, __last,
				__gnu_cxx::__ops::__iter_less_iter());
    }

/**
   *  @brief  Return the minimum element in a range using comparison functor.
   *  @ingroup sorting_algorithms
   *  @param  __first  Start of range.
   *  @param  __last   End of range.
   *  @param  __comp   Comparison functor.
   *  @return  Iterator referencing the first instance of the smallest value
   *  according to __comp.
  */
  template<typename _ForwardIterator, typename _Compare>
    _GLIBCXX14_CONSTEXPR
    inline _ForwardIterator
    min_element(_ForwardIterator __first, _ForwardIterator __last,
		_Compare __comp)
    {
      // concept requirements
      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
	    typename iterator_traits<_ForwardIterator>::value_type,
	    typename iterator_traits<_ForwardIterator>::value_type>)
      __glibcxx_requires_valid_range(__first, __last);
      __glibcxx_requires_irreflexive_pred(__first, __last, __comp);

return _GLIBCXX_STD_A::__min_element(__first, __last,
				__gnu_cxx::__ops::__iter_comp_iter(__comp));
    }

template<typename _ForwardIterator, typename _Compare>
    _GLIBCXX14_CONSTEXPR
    _ForwardIterator
    __max_element(_ForwardIterator __first, _ForwardIterator __last,
		  _Compare __comp)
    {
      if (__first == __last) return __first;
      _ForwardIterator __result = __first;
      while (++__first != __last)
	if (__comp(__result, __first))
	  __result = __first;
      return __result;
    }

/**
   *  @brief  Return the maximum element in a range.
   *  @ingroup sorting_algorithms
   *  @param  __first  Start of range.
   *  @param  __last   End of range.
   *  @return  Iterator referencing the first instance of the largest value.
  */
  template<typename _ForwardIterator>
    _GLIBCXX14_CONSTEXPR
    inline _ForwardIterator
    max_element(_ForwardIterator __first, _ForwardIterator __last)
    {
      // concept requirements
      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
      __glibcxx_function_requires(_LessThanComparableConcept<
	    typename iterator_traits<_ForwardIterator>::value_type>)
      __glibcxx_requires_valid_range(__first, __last);
      __glibcxx_requires_irreflexive(__first, __last);

return _GLIBCXX_STD_A::__max_element(__first, __last,
				__gnu_cxx::__ops::__iter_less_iter());
    }

/**
   *  @brief  Return the maximum element in a range using comparison functor.
   *  @ingroup sorting_algorithms
   *  @param  __first  Start of range.
   *  @param  __last   End of range.
   *  @param  __comp   Comparison functor.
   *  @return  Iterator referencing the first instance of the largest value
   *  according to __comp.
  */
  template<typename _ForwardIterator, typename _Compare>
    _GLIBCXX14_CONSTEXPR
    inline _ForwardIterator
    max_element(_ForwardIterator __first, _ForwardIterator __last,
		_Compare __comp)
    {
      // concept requirements
      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
	    typename iterator_traits<_ForwardIterator>::value_type,
	    typename iterator_traits<_ForwardIterator>::value_type>)
      __glibcxx_requires_valid_range(__first, __last);
      __glibcxx_requires_irreflexive_pred(__first, __last, __comp);

return _GLIBCXX_STD_A::__max_element(__first, __last,
				__gnu_cxx::__ops::__iter_comp_iter(__comp));
    }

#if __cplusplus >= 201402L
  /// Reservoir sampling algorithm.
  template<typename _InputIterator, typename _RandomAccessIterator,
           typename _Size, typename _UniformRandomBitGenerator>
    _RandomAccessIterator
    __sample(_InputIterator __first, _InputIterator __last, input_iterator_tag,
	     _RandomAccessIterator __out, random_access_iterator_tag,
	     _Size __n, _UniformRandomBitGenerator&& __g)
    {
      using __distrib_type = uniform_int_distribution<_Size>;
      using __param_type = typename __distrib_type::param_type;
      __distrib_type __d{};
      _Size __sample_sz = 0;
      while (__first != __last && __sample_sz != __n)
	{
	  __out[__sample_sz++] = *__first;
	  ++__first;
	}
      for (auto __pop_sz = __sample_sz; __first != __last;
	  ++__first, (void) ++__pop_sz)
	{
	  const auto __k = __d(__g, __param_type{0, __pop_sz});
	  if (__k < __n)
	    __out[__k] = *__first;
	}
      return __out + __sample_sz;
    }

/// Selection sampling algorithm.
  template<typename _ForwardIterator, typename _OutputIterator, typename _Cat,
           typename _Size, typename _UniformRandomBitGenerator>
    _OutputIterator
    __sample(_ForwardIterator __first, _ForwardIterator __last,
	     forward_iterator_tag,
	     _OutputIterator __out, _Cat,
	     _Size __n, _UniformRandomBitGenerator&& __g)
    {
      using __distrib_type = uniform_int_distribution<_Size>;
      using __param_type = typename __distrib_type::param_type;
      using _USize = make_unsigned_t<_Size>;
      using _Gen = remove_reference_t<_UniformRandomBitGenerator>;
      using __uc_type = common_type_t<typename _Gen::result_type, _USize>;

if (__first == __last)
	return __out;

__distrib_type __d{};
      _Size __unsampled_sz = std::distance(__first, __last);
      __n = std::min(__n, __unsampled_sz);

// If possible, we use __gen_two_uniform_ints to efficiently produce
      // two random numbers using a single distribution invocation:

const __uc_type __urngrange = __g.max() - __g.min();
      if (__urngrange / __uc_type(__unsampled_sz) >= __uc_type(__unsampled_sz))
        // I.e. (__urngrange >= __unsampled_sz * __unsampled_sz) but without
	// wrapping issues.
        {
	  while (__n != 0 && __unsampled_sz >= 2)
	    {
	      const pair<_Size, _Size> __p =
		__gen_two_uniform_ints(__unsampled_sz, __unsampled_sz - 1, __g);

--__unsampled_sz;
	      if (__p.first < __n)
		{
		  *__out++ = *__first;
		  --__n;
		}

++__first;

if (__n == 0) break;

--__unsampled_sz;
	      if (__p.second < __n)
		{
		  *__out++ = *__first;
		  --__n;
		}

++__first;
	    }
        }

// The loop above is otherwise equivalent to this one-at-a-time version:

for (; __n != 0; ++__first)
	if (__d(__g, __param_type{0, --__unsampled_sz}) < __n)
	  {
	    *__out++ = *__first;
	    --__n;
	  }
      return __out;
    }

#if __cplusplus > 201402L
#define __cpp_lib_sample 201603
  /// Take a random sample from a population.
  template<typename _PopulationIterator, typename _SampleIterator,
           typename _Distance, typename _UniformRandomBitGenerator>
    _SampleIterator
    sample(_PopulationIterator __first, _PopulationIterator __last,
	   _SampleIterator __out, _Distance __n,
	   _UniformRandomBitGenerator&& __g)
    {
      using __pop_cat = typename
	std::iterator_traits<_PopulationIterator>::iterator_category;
      using __samp_cat = typename
	std::iterator_traits<_SampleIterator>::iterator_category;

static_assert(
	  __or_<is_convertible<__pop_cat, forward_iterator_tag>,
		is_convertible<__samp_cat, random_access_iterator_tag>>::value,
	  "output range must use a RandomAccessIterator when input range"
	  " does not meet the ForwardIterator requirements");

static_assert(is_integral<_Distance>::value,
		    "sample size must be an integer type");

typename iterator_traits<_PopulationIterator>::difference_type __d = __n;
      return _GLIBCXX_STD_A::
	__sample(__first, __last, __pop_cat{}, __out, __samp_cat{}, __d,
		 std::forward<_UniformRandomBitGenerator>(__g));
    }
#endif // C++17
#endif // C++14

_GLIBCXX_END_NAMESPACE_ALGO
_GLIBCXX_END_NAMESPACE_VERSION
} // namespace std

#endif /* _STL_ALGO_H */

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