v1/__algorithm/make_heap.h

0001 //===----------------------------------------------------------------------===//
0002 //
0003 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
0004 // See https://llvm.org/LICENSE.txt for license information.
0005 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
0006 //
0007 //===----------------------------------------------------------------------===//
0008
0009 #ifndef _LIBCPP___ALGORITHM_MAKE_HEAP_H
0010 #define _LIBCPP___ALGORITHM_MAKE_HEAP_H
0011
0012 #include <__algorithm/comp.h>
0013 #include <__algorithm/comp_ref_type.h>
0014 #include <__algorithm/iterator_operations.h>
0015 #include <__algorithm/sift_down.h>
0016 #include <__config>
0017 #include <__iterator/iterator_traits.h>
0018 #include <__utility/move.h>
0019
0020 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
0021 #  pragma GCC system_header
0022 #endif
0023
0024 _LIBCPP_PUSH_MACROS
0025 #include <__undef_macros>
0026
0027 _LIBCPP_BEGIN_NAMESPACE_STD
0028
0029 template <class _AlgPolicy, class _Compare, class _RandomAccessIterator>
0030 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 void
0031 __make_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare&& __comp) {
0032   __comp_ref_type<_Compare> __comp_ref = __comp;
0033
0034   using difference_type = typename iterator_traits<_RandomAccessIterator>::difference_type;
0035   difference_type __n   = __last - __first;
0036   if (__n > 1) {
0037     // start from the first parent, there is no need to consider children
0038     for (difference_type __start = (__n - 2) / 2; __start >= 0; --__start) {
0039       std::__sift_down<_AlgPolicy>(__first, __comp_ref, __n, __first + __start);
0040     }
0041   }
0042 }
0043
0044 template <class _RandomAccessIterator, class _Compare>
0045 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void
0046 make_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp) {
0047   std::__make_heap<_ClassicAlgPolicy>(std::move(__first), std::move(__last), __comp);
0048 }
0049
0050 template <class _RandomAccessIterator>
0051 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void
0052 make_heap(_RandomAccessIterator __first, _RandomAccessIterator __last) {
0053   std::make_heap(std::move(__first), std::move(__last), __less<>());
0054 }
0055
0056 _LIBCPP_END_NAMESPACE_STD
0057
0058 _LIBCPP_POP_MACROS
0059
0060 #endif // _LIBCPP___ALGORITHM_MAKE_HEAP_H