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81 lines
3 KiB
C++
81 lines
3 KiB
C++
//===----------------------------------------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#ifndef _LIBCPP___ALGORITHM_POP_HEAP_H
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#define _LIBCPP___ALGORITHM_POP_HEAP_H
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#include <__algorithm/comp.h>
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#include <__algorithm/comp_ref_type.h>
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#include <__algorithm/iterator_operations.h>
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#include <__algorithm/push_heap.h>
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#include <__algorithm/sift_down.h>
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#include <__assert>
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#include <__config>
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#include <__iterator/iterator_traits.h>
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#include <__type_traits/is_assignable.h>
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#include <__type_traits/is_constructible.h>
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#include <__utility/move.h>
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#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
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# pragma GCC system_header
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#endif
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_LIBCPP_PUSH_MACROS
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#include <__undef_macros>
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_LIBCPP_BEGIN_NAMESPACE_STD
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template <class _AlgPolicy, class _Compare, class _RandomAccessIterator>
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inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 void
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__pop_heap(_RandomAccessIterator __first,
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_RandomAccessIterator __last,
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_Compare& __comp,
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typename iterator_traits<_RandomAccessIterator>::difference_type __len) {
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// Calling `pop_heap` on an empty range is undefined behavior, but in practice it will be a no-op.
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_LIBCPP_ASSERT_PEDANTIC(__len > 0, "The heap given to pop_heap must be non-empty");
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__comp_ref_type<_Compare> __comp_ref = __comp;
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using value_type = typename iterator_traits<_RandomAccessIterator>::value_type;
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if (__len > 1) {
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value_type __top = _IterOps<_AlgPolicy>::__iter_move(__first); // create a hole at __first
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_RandomAccessIterator __hole = std::__floyd_sift_down<_AlgPolicy>(__first, __comp_ref, __len);
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--__last;
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if (__hole == __last) {
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*__hole = std::move(__top);
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} else {
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*__hole = _IterOps<_AlgPolicy>::__iter_move(__last);
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++__hole;
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*__last = std::move(__top);
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std::__sift_up<_AlgPolicy>(__first, __hole, __comp_ref, __hole - __first);
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}
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}
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}
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template <class _RandomAccessIterator, class _Compare>
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inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void
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pop_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp) {
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static_assert(std::is_copy_constructible<_RandomAccessIterator>::value, "Iterators must be copy constructible.");
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static_assert(std::is_copy_assignable<_RandomAccessIterator>::value, "Iterators must be copy assignable.");
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typename iterator_traits<_RandomAccessIterator>::difference_type __len = __last - __first;
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std::__pop_heap<_ClassicAlgPolicy>(std::move(__first), std::move(__last), __comp, __len);
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}
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template <class _RandomAccessIterator>
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inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void
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pop_heap(_RandomAccessIterator __first, _RandomAccessIterator __last) {
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std::pop_heap(std::move(__first), std::move(__last), __less<>());
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}
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_LIBCPP_END_NAMESPACE_STD
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_LIBCPP_POP_MACROS
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#endif // _LIBCPP___ALGORITHM_POP_HEAP_H
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