468 lines
16 KiB
C++
468 lines
16 KiB
C++
// Heap implementation -*- C++ -*-
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// Copyright (C) 2001, 2004 Free Software Foundation, Inc.
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//
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// This file is part of the GNU ISO C++ Library. This library is free
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// software; you can redistribute it and/or modify it under the
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// terms of the GNU General Public License as published by the
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// Free Software Foundation; either version 2, or (at your option)
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// any later version.
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// This library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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// You should have received a copy of the GNU General Public License along
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// with this library; see the file COPYING. If not, write to the Free
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// Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307,
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// USA.
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// As a special exception, you may use this file as part of a free software
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// library without restriction. Specifically, if other files instantiate
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// templates or use macros or inline functions from this file, or you compile
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// this file and link it with other files to produce an executable, this
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// file does not by itself cause the resulting executable to be covered by
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// the GNU General Public License. This exception does not however
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// invalidate any other reasons why the executable file might be covered by
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// the GNU General Public License.
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/*
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*
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* Copyright (c) 1994
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* Hewlett-Packard Company
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*
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* Permission to use, copy, modify, distribute and sell this software
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* and its documentation for any purpose is hereby granted without fee,
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* provided that the above copyright notice appear in all copies and
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* that both that copyright notice and this permission notice appear
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* in supporting documentation. Hewlett-Packard Company makes no
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* representations about the suitability of this software for any
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* purpose. It is provided "as is" without express or implied warranty.
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*
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* Copyright (c) 1997
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* Silicon Graphics Computer Systems, Inc.
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*
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* Permission to use, copy, modify, distribute and sell this software
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* and its documentation for any purpose is hereby granted without fee,
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* provided that the above copyright notice appear in all copies and
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* that both that copyright notice and this permission notice appear
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* in supporting documentation. Silicon Graphics makes no
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* representations about the suitability of this software for any
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* purpose. It is provided "as is" without express or implied warranty.
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*/
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/** @file stl_heap.h
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* This is an internal header file, included by other library headers.
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* You should not attempt to use it directly.
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*/
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#ifndef _STL_HEAP_H
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#define _STL_HEAP_H 1
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#include <debug/debug.h>
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namespace std
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{
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// is_heap, a predicate testing whether or not a range is
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// a heap. This function is an extension, not part of the C++
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// standard.
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template<typename _RandomAccessIterator, typename _Distance>
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bool
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__is_heap(_RandomAccessIterator __first, _Distance __n)
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{
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_Distance __parent = 0;
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for (_Distance __child = 1; __child < __n; ++__child)
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{
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if (__first[__parent] < __first[__child])
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return false;
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if ((__child & 1) == 0)
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++__parent;
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}
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return true;
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}
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template<typename _RandomAccessIterator, typename _Distance,
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typename _StrictWeakOrdering>
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bool
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__is_heap(_RandomAccessIterator __first, _StrictWeakOrdering __comp,
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_Distance __n)
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{
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_Distance __parent = 0;
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for (_Distance __child = 1; __child < __n; ++__child)
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{
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if (__comp(__first[__parent], __first[__child]))
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return false;
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if ((__child & 1) == 0)
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++__parent;
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}
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return true;
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}
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template<typename _RandomAccessIterator>
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bool
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__is_heap(_RandomAccessIterator __first, _RandomAccessIterator __last)
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{ return std::__is_heap(__first, std::distance(__first, __last)); }
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template<typename _RandomAccessIterator, typename _StrictWeakOrdering>
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bool
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__is_heap(_RandomAccessIterator __first, _RandomAccessIterator __last,
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_StrictWeakOrdering __comp)
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{ return std::__is_heap(__first, __comp, std::distance(__first, __last)); }
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// Heap-manipulation functions: push_heap, pop_heap, make_heap, sort_heap.
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template<typename _RandomAccessIterator, typename _Distance, typename _Tp>
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void
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__push_heap(_RandomAccessIterator __first,
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_Distance __holeIndex, _Distance __topIndex, _Tp __value)
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{
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_Distance __parent = (__holeIndex - 1) / 2;
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while (__holeIndex > __topIndex && *(__first + __parent) < __value)
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{
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*(__first + __holeIndex) = *(__first + __parent);
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__holeIndex = __parent;
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__parent = (__holeIndex - 1) / 2;
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}
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*(__first + __holeIndex) = __value;
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}
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/**
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* @brief Push an element onto a heap.
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* @param first Start of heap.
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* @param last End of heap + element.
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* @ingroup heap
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*
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* This operation pushes the element at last-1 onto the valid heap over the
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* range [first,last-1). After completion, [first,last) is a valid heap.
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*/
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template<typename _RandomAccessIterator>
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inline void
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push_heap(_RandomAccessIterator __first, _RandomAccessIterator __last)
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{
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typedef typename iterator_traits<_RandomAccessIterator>::value_type
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_ValueType;
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typedef typename iterator_traits<_RandomAccessIterator>::difference_type
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_DistanceType;
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// concept requirements
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__glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
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_RandomAccessIterator>)
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__glibcxx_function_requires(_LessThanComparableConcept<_ValueType>)
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__glibcxx_requires_valid_range(__first, __last);
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// __glibcxx_requires_heap(__first, __last - 1);
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std::__push_heap(__first, _DistanceType((__last - __first) - 1),
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_DistanceType(0), _ValueType(*(__last - 1)));
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}
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template<typename _RandomAccessIterator, typename _Distance, typename _Tp,
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typename _Compare>
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void
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__push_heap(_RandomAccessIterator __first, _Distance __holeIndex,
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_Distance __topIndex, _Tp __value, _Compare __comp)
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{
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_Distance __parent = (__holeIndex - 1) / 2;
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while (__holeIndex > __topIndex
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&& __comp(*(__first + __parent), __value))
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{
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*(__first + __holeIndex) = *(__first + __parent);
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__holeIndex = __parent;
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__parent = (__holeIndex - 1) / 2;
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}
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*(__first + __holeIndex) = __value;
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}
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/**
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* @brief Push an element onto a heap using comparison functor.
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* @param first Start of heap.
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* @param last End of heap + element.
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* @param comp Comparison functor.
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* @ingroup heap
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*
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* This operation pushes the element at last-1 onto the valid heap over the
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* range [first,last-1). After completion, [first,last) is a valid heap.
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* Compare operations are performed using comp.
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*/
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template<typename _RandomAccessIterator, typename _Compare>
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inline void
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push_heap(_RandomAccessIterator __first, _RandomAccessIterator __last,
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_Compare __comp)
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{
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typedef typename iterator_traits<_RandomAccessIterator>::value_type
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_ValueType;
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typedef typename iterator_traits<_RandomAccessIterator>::difference_type
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_DistanceType;
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// concept requirements
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__glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
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_RandomAccessIterator>)
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__glibcxx_requires_valid_range(__first, __last);
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__glibcxx_requires_heap_pred(__first, __last - 1, __comp);
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std::__push_heap(__first, _DistanceType((__last - __first) - 1),
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_DistanceType(0), _ValueType(*(__last - 1)), __comp);
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}
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template<typename _RandomAccessIterator, typename _Distance, typename _Tp>
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void
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__adjust_heap(_RandomAccessIterator __first, _Distance __holeIndex,
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_Distance __len, _Tp __value)
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{
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const _Distance __topIndex = __holeIndex;
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_Distance __secondChild = 2 * __holeIndex + 2;
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while (__secondChild < __len)
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{
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if (*(__first + __secondChild) < *(__first + (__secondChild - 1)))
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__secondChild--;
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*(__first + __holeIndex) = *(__first + __secondChild);
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__holeIndex = __secondChild;
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__secondChild = 2 * (__secondChild + 1);
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}
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if (__secondChild == __len)
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{
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*(__first + __holeIndex) = *(__first + (__secondChild - 1));
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__holeIndex = __secondChild - 1;
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}
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std::__push_heap(__first, __holeIndex, __topIndex, __value);
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}
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template<typename _RandomAccessIterator, typename _Tp>
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inline void
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__pop_heap(_RandomAccessIterator __first, _RandomAccessIterator __last,
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_RandomAccessIterator __result, _Tp __value)
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{
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typedef typename iterator_traits<_RandomAccessIterator>::difference_type
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_Distance;
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*__result = *__first;
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std::__adjust_heap(__first, _Distance(0), _Distance(__last - __first),
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__value);
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}
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/**
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* @brief Pop an element off a heap.
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* @param first Start of heap.
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* @param last End of heap.
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* @ingroup heap
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*
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* This operation pops the top of the heap. The elements first and last-1
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* are swapped and [first,last-1) is made into a heap.
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*/
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template<typename _RandomAccessIterator>
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inline void
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pop_heap(_RandomAccessIterator __first, _RandomAccessIterator __last)
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{
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typedef typename iterator_traits<_RandomAccessIterator>::value_type
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_ValueType;
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// concept requirements
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__glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
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_RandomAccessIterator>)
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__glibcxx_function_requires(_LessThanComparableConcept<_ValueType>)
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__glibcxx_requires_valid_range(__first, __last);
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__glibcxx_requires_heap(__first, __last);
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std::__pop_heap(__first, __last - 1, __last - 1,
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_ValueType(*(__last - 1)));
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}
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template<typename _RandomAccessIterator, typename _Distance,
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typename _Tp, typename _Compare>
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void
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__adjust_heap(_RandomAccessIterator __first, _Distance __holeIndex,
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_Distance __len, _Tp __value, _Compare __comp)
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{
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const _Distance __topIndex = __holeIndex;
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_Distance __secondChild = 2 * __holeIndex + 2;
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while (__secondChild < __len)
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{
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if (__comp(*(__first + __secondChild),
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*(__first + (__secondChild - 1))))
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__secondChild--;
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*(__first + __holeIndex) = *(__first + __secondChild);
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__holeIndex = __secondChild;
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__secondChild = 2 * (__secondChild + 1);
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}
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if (__secondChild == __len)
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{
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*(__first + __holeIndex) = *(__first + (__secondChild - 1));
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__holeIndex = __secondChild - 1;
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}
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std::__push_heap(__first, __holeIndex, __topIndex, __value, __comp);
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}
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template<typename _RandomAccessIterator, typename _Tp, typename _Compare>
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inline void
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__pop_heap(_RandomAccessIterator __first, _RandomAccessIterator __last,
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_RandomAccessIterator __result, _Tp __value, _Compare __comp)
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{
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typedef typename iterator_traits<_RandomAccessIterator>::difference_type
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_Distance;
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*__result = *__first;
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std::__adjust_heap(__first, _Distance(0), _Distance(__last - __first),
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__value, __comp);
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}
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/**
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* @brief Pop an element off a heap using comparison functor.
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* @param first Start of heap.
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* @param last End of heap.
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* @param comp Comparison functor to use.
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* @ingroup heap
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*
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* This operation pops the top of the heap. The elements first and last-1
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* are swapped and [first,last-1) is made into a heap. Comparisons are
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* made using comp.
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*/
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template<typename _RandomAccessIterator, typename _Compare>
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inline void
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pop_heap(_RandomAccessIterator __first,
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_RandomAccessIterator __last, _Compare __comp)
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{
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// concept requirements
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__glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
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_RandomAccessIterator>)
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__glibcxx_requires_valid_range(__first, __last);
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__glibcxx_requires_heap_pred(__first, __last, __comp);
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typedef typename iterator_traits<_RandomAccessIterator>::value_type
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_ValueType;
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std::__pop_heap(__first, __last - 1, __last - 1,
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_ValueType(*(__last - 1)), __comp);
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}
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/**
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* @brief Construct a heap over a range.
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* @param first Start of heap.
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* @param last End of heap.
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* @ingroup heap
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*
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* This operation makes the elements in [first,last) into a heap.
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*/
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template<typename _RandomAccessIterator>
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void
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make_heap(_RandomAccessIterator __first, _RandomAccessIterator __last)
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{
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typedef typename iterator_traits<_RandomAccessIterator>::value_type
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_ValueType;
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typedef typename iterator_traits<_RandomAccessIterator>::difference_type
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_DistanceType;
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// concept requirements
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__glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
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_RandomAccessIterator>)
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__glibcxx_function_requires(_LessThanComparableConcept<_ValueType>)
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__glibcxx_requires_valid_range(__first, __last);
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if (__last - __first < 2)
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return;
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const _DistanceType __len = __last - __first;
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_DistanceType __parent = (__len - 2) / 2;
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while (true)
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{
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std::__adjust_heap(__first, __parent, __len,
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_ValueType(*(__first + __parent)));
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if (__parent == 0)
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return;
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__parent--;
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}
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}
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/**
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* @brief Construct a heap over a range using comparison functor.
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* @param first Start of heap.
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* @param last End of heap.
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* @param comp Comparison functor to use.
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* @ingroup heap
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*
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* This operation makes the elements in [first,last) into a heap.
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* Comparisons are made using comp.
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*/
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template<typename _RandomAccessIterator, typename _Compare>
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inline void
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make_heap(_RandomAccessIterator __first, _RandomAccessIterator __last,
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_Compare __comp)
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{
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typedef typename iterator_traits<_RandomAccessIterator>::value_type
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_ValueType;
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typedef typename iterator_traits<_RandomAccessIterator>::difference_type
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_DistanceType;
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// concept requirements
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__glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
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_RandomAccessIterator>)
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__glibcxx_requires_valid_range(__first, __last);
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if (__last - __first < 2)
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return;
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const _DistanceType __len = __last - __first;
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_DistanceType __parent = (__len - 2) / 2;
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while (true)
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{
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std::__adjust_heap(__first, __parent, __len,
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_ValueType(*(__first + __parent)), __comp);
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if (__parent == 0)
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return;
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__parent--;
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}
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}
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/**
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* @brief Sort a heap.
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* @param first Start of heap.
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* @param last End of heap.
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* @ingroup heap
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*
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* This operation sorts the valid heap in the range [first,last).
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*/
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template<typename _RandomAccessIterator>
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void
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sort_heap(_RandomAccessIterator __first, _RandomAccessIterator __last)
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{
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// concept requirements
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__glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
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_RandomAccessIterator>)
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__glibcxx_function_requires(_LessThanComparableConcept<
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typename iterator_traits<_RandomAccessIterator>::value_type>)
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__glibcxx_requires_valid_range(__first, __last);
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// __glibcxx_requires_heap(__first, __last);
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while (__last - __first > 1)
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std::pop_heap(__first, __last--);
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}
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/**
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* @brief Sort a heap using comparison functor.
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* @param first Start of heap.
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* @param last End of heap.
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* @param comp Comparison functor to use.
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* @ingroup heap
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*
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* This operation sorts the valid heap in the range [first,last).
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* Comparisons are made using comp.
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*/
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template<typename _RandomAccessIterator, typename _Compare>
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void
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sort_heap(_RandomAccessIterator __first, _RandomAccessIterator __last,
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_Compare __comp)
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{
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// concept requirements
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__glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
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_RandomAccessIterator>)
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__glibcxx_requires_valid_range(__first, __last);
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__glibcxx_requires_heap_pred(__first, __last, __comp);
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while (__last - __first > 1)
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std::pop_heap(__first, __last--, __comp);
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}
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} // namespace std
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#endif /* _STL_HEAP_H */
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// Local Variables:
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// mode:C++
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// End:
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