std::is_sorted_until
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在头文件 <algorithm> 中定义
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template< class ForwardIt > ForwardIt is_sorted_until( ForwardIt first, ForwardIt last ); |
(1) | (C++11 起) |
template< class ForwardIt, class Compare > ForwardIt is_sorted_until( ForwardIt first, ForwardIt last, |
(2) | (C++11 起) |
检查的范围
[first, last)
发现的最大范围内开始在first
中的元素按升序排序。 operator<的第一个版本的功能使用比较的元素,第二个使用给定的比较函数comp
.原文:
Examines the range
[first, last)
and finds the largest range beginning at first
in which the elements are sorted in ascending order. The first version of the function uses operator< to compare the elements, the second uses the given comparison function comp
.目录 |
[编辑] 参数
first, last | - | 检查的元素
|
comp | - | comparison function which returns true if the first argument is less than the second. The signature of the comparison function should be equivalent to the following: bool cmp(const Type1 &a, const Type2 &b); The signature does not need to have const &, but the function must not modify the objects passed to it. |
类型要求 | ||
-ForwardIt 必须满足 ForwardIterator 的要求。
|
[编辑] 返回值
的上限,最大范围的开始,
first
中的元素按升序排序。即,最后的迭代器的排序条件范围it
[first, it)
.原文:
The upper bound of the largest range beginning at
first
in which the elements are sorted in ascending order. That is, the last iterator it
for which range [first, it)
is sorted.[编辑] 复杂度
线性
first
和last
之间的距离原文:
linear in the distance between
first
and last
[编辑] 可能的实现
版本一 |
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template<class ForwardIt> ForwardIt is_sorted_until(ForwardIt first, ForwardIt last) { if (first != last) { ForwardIt next = first; while (++next != last) { if (*next < *first) return next; first = next; } } return last; } |
版本二 |
template< class ForwardIt, class Compare > ForwardIt is_sorted_until(ForwardIt first, ForwardIt last, Compare comp) { if (first != last) { ForwardIt next = first; while (++next != last) { if (comp(*next, *first)) return next; first = next; } } return last; |
[编辑] 示例
#include <iostream> #include <algorithm> #include <iterator> #include <random> int main() { std::random_device rd; std::mt19937 g(rd()); const int N = 6; int nums[N] = {3, 1, 4, 1, 5, 9}; const int min_sorted_size = 4; int sorted_size = 0; do { std::random_shuffle(nums, nums + N, g); int *sorted_end = std::is_sorted_until(nums, nums + N); sorted_size = std::distance(nums, sorted_end); for (auto i : nums) std::cout << i << ' '; std::cout << " : " << sorted_size << " initial sorted elements\n"; } while (sorted_size < min_sorted_size); }
Possible output:
4 1 9 5 1 3 : 1 initial sorted elements 4 5 9 3 1 1 : 3 initial sorted elements 9 3 1 4 5 1 : 1 initial sorted elements 1 3 5 4 1 9 : 3 initial sorted elements 5 9 1 1 3 4 : 2 initial sorted elements 4 9 1 5 1 3 : 2 initial sorted elements 1 1 4 9 5 3 : 4 initial sorted elements
[编辑] 另请参阅
(C++11) |
检查区间是否按升序排列 (函数模板) |