std::min_element
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在头文件 <algorithm> 中定义
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template< class ForwardIt > ForwardIt min_element( ForwardIt first, ForwardIt last ); |
(1) | |
template< class ForwardIt, class Compare > ForwardIt min_element( ForwardIt first, ForwardIt last, Compare comp ); |
(2) | |
查找的范围内
[first, last)
中最小的元素。使用operator<的值进行比较的第一个版本,第二个版本使用给定的比较函数comp
.原文:
Finds the smallest element in the range
[first, last)
. The first version uses operator< to compare the values, the second version uses the given comparison function comp
.目录 |
[编辑] 参数
first, last | - | 前向迭代器定义的范围检查
原文: forward iterators defining the range to examine |
cmp | - | comparison function which returns true if if *a is less than *b . 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。
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[编辑] 返回值
迭代器的范围内
[first, last)
最小的元素。如果几个元素的取值范围为最小的元素是等价的,返回的迭代器的第一个这样的元件。返回last
的范围内是空原文:
Iterator to the smallest element in the range
[first, last)
. If several elements in the range are equivalent to the smallest element, returns the iterator to the first such element. Returns last
if the range is empty.[编辑] 复杂度
究竟max(N-1,0)比较,N = std::distance(first, last).
原文:
Exactly max(N-1,0) comparisons, where N = std::distance(first, last).
[编辑] 可能的实现
版本一 |
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template<class ForwardIt> ForwardIt min_element(ForwardIt first, ForwardIt last) { if (first == last) return last; ForwardIt smallest = first; ++first; for (; first != last; ++first) { if (*first < *smallest) { smallest = first; } } return smallest; } |
版本二 |
template<class ForwardIt, class Compare> ForwardIt min_element(ForwardIt first, ForwardIt last, Compare comp) { if (first == last) return last; ForwardIt smallest = first; ++first; for (; first != last; ++first) { if (comp(*first, *smallest)) { smallest = first; } } return smallest; } |
[编辑] 示例
#include <algorithm> #include <iostream> #include <vector> int main() { std::vector<int> v{3, 1, 4, 1, 5, 9}; std::vector<int>::iterator result = std::min_element(v.begin(), v.end()); std::cout << "min element at: " << std::distance(v.begin(), result); }
输出:
min element at: 1
[编辑] 另请参阅
返回区间内的最大元素 (函数模板) | |
(C++11) |
返回区间内的最小元素和最大元素 (函数模板) |
返回两个元素中的较小者 (函数模板) |