ranges_is_heap.md

is_heap

• algorithm[meta header]
• std::ranges[meta namespace]
• function template[meta id-type]
• cpp20[meta cpp]

namespace std::ranges {
  template <random_access_iterator I,
            sentinel_for<I> S,
            class Proj = identity,
            indirect_strict_weak_order<projected<I, Proj>> Comp = ranges::less>
  constexpr bool
    is_heap(I first,
            S last,
            Comp comp = {},
            Proj proj = {}); // (1) C++20

  template <random_access_range R,
            class Proj = identity,
            indirect_strict_weak_order<projected<iterator_t<R>, Proj>> Comp = ranges::less>
  constexpr bool
    is_heap(R&& r,
            Comp comp = {},
            Proj proj = {}); // (2) C++20
}

• random_access_iterator[link /reference/iterator/random_access_iterator.md]
• sentinel_for[link /reference/iterator/sentinel_for.md]
• ranges::less[link /reference/functional/ranges_less.md]
• identity[link /reference/functional/identity.md]
• indirect_strict_weak_order[link /reference/iterator/indirect_strict_weak_order.md]
• random_access_range[link /reference/ranges/random_access_range.md]
• iterator_t[link /reference/ranges/iterator_t.md]

概要

範囲がヒープ化されているか判定する。

• (1): イテレータ範囲を指定する
• (2): Rangeを直接指定する

効果

ranges::is_heap_until(first, last, comp, proj) == last と等しい。

例

#include <iostream>
#include <vector>
#include <algorithm>

int main()
{
  std::vector<int> v = {3, 1, 4};

  std::cout << std::boolalpha;

  std::cout << "before: is heap? "
            << std::ranges::is_heap(v) << std::endl;

  std::ranges::make_heap(v);
  std::cout << " after: is heap? "
            << std::ranges::is_heap(v) << std::endl;
}

• std::ranges::is_heap[color ff0000]
• std::ranges::make_heap[link ranges_make_heap.md]

出力

before: is heap? false
 after: is heap? true

バージョン

言語

• C++20

処理系

• Clang: ??
• GCC: 10.1.0
• ICC: ??
• Visual C++: 2019 Update 10

参照

• N4861 25 Algorithms library