std::partition_point
Defined in header <algorithm> | ? | ? |
|---|---|---|
template< class ForwardIt, class UnaryPredicate > ForwardIt partition_point( ForwardIt first, ForwardIt last, UnaryPredicate p ); | (1) | (since C++11) |
检查分区%28，如果std::partition%29范围[first, last)并定位第一个分区的末尾，即不满足的第一个元素。p或last如果所有元素都满足p...
参数
first, last | - | the partitioned range of elements to examine |
|---|---|---|
p | - | unary predicate which returns ?true for the elements found in the beginning of the range. The signature of the predicate function should be equivalent to the following: bool pred(const Type &a); The signature does not need to have const &, but the function must not modify the objects passed to it. The type Type must be such that an object of type ForwardIt can be dereferenced and then implicitly converted to Type. ? |
类型要求
---。
-单数预测必须满足谓词的要求。
返回值
中的第一个分区结束后的迭代器。[first, last)或last如果所有元素都满足p...
复杂性
O%28 log%28N%29%29，其中N =std::distance(first, last)，谓词p的应用。
例
二次
#include <algorithm>
#include <array>
#include <iostream>
#include <iterator>
int main()
{
std::array<int, 9> v = { 1, 2, 3, 4, 5, 6, 7, 8, 9 };
auto is_even = [](int i){ return i % 2 == 0; };
std::partition(v.begin(), v.end(), is_even);
auto p = std::partition_point(v.begin(), v.end(), is_even);
std::cout << "Before partition:\n ";
std::copy(v.begin(), p, std::ostream_iterator<int>(std::cout, " "));
std::cout << "\nAfter partition:\n ";
std::copy(p, v.end(), std::ostream_iterator<int>(std::cout, " "));
}二次
产出：
二次
Before partition:
8 2 6 4
After partition:
5 3 7 1 9二次
另见
is_sorted (C++11) | checks whether a range is sorted into ascending order (function template) |
|---|
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