std::is_heap_until

[]	Google. . , . , . ( . .)

`<algorithm>`
`template< class RandomIt > RandomIt is_heap_until( RandomIt first, RandomIt last );`	(1)	( C++11)
`template< class RandomIt, class Compare > RandomIt is_heap_until( RandomIt first, RandomIt last, Compare comp );`	(2)	( C++11)

[first, last) first ' . operator< , comp.
:
Examines the range [first, last) and finds the largest range beginning at first which is heap. The first version of the function uses operator< to compare the elements, the second uses the given comparison function comp.
Google.
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first, last		: the range of elements to examine Google. . .
comp		(.. , Compare), `true`, "", . : `bool cmp(const Type1 &a, const Type2 &b);` `noexcept` ( C++11) . `const&`, . ( `const`) `Type1` `Type2` ( , `Type1&` , `Type1`, `Type1` ( C++11)). `Type1` `Type2` , `RandomIt` .

- `RandomIt` `RandomAccessIterator`.

first ' . , it , [first, it) ' .

first last

' [f,l), :
:
A heap is a range of elements [f,l) that has the following properties:
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. .

*f
:
*f is the largest element in the range
Google.
. .
std::push_heap()
:
a new element can be added using std::push_heap()
Google.
. .
std::pop_heap()
:
the first element can be removed using std::pop_heap()
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, .

#include <iostream>
#include <algorithm>

int main()
{
    std::vector<int> v { 3, 1, 4, 1, 5, 9 };

    std::make_heap(v.begin(), v.end());

    // probably mess up the heap
    v.push_back(2);
    v.push_back(6);

    auto heap_end = std::is_heap_until(v.begin(), v.end());

    std::cout << "all of v: ";
    for (auto i : v) std::cout << i << ' ';
    std::cout << '\n';

    std::cout << "only heap: ";
    for (auto i = v.begin(); i != heap_end; ++i) std::cout << *i << ' ';
    std::cout << '\n';
}

:

all of v:  9 5 4 1 1 3 2 6
only heap: 9 5 4 1 1 3 2

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is_heap

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( ) []







(C++20)

(C++20)
(C++11)





(C++20)


/

(C++11)
(C++11)
(C++11)
(C++17)

cppreference.com

std::is_heap_until

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