std::min_element

 

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Defined in header <algorithm>
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.

Original:

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.

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参数

first, last	-	前向迭代器定义的范围检查 Original: forward iterators defining the range to examine The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
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. The types  Type1 and  Type2 must be such that an object of type ForwardIt can be dereferenced and then implicitly converted to both of them. ​
Type requirements
- ForwardIt must meet the requirements of ForwardIterator.

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

Original:

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.

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复杂性

究竟max(N-1,0)比较，N = std::distance(first, last).

Original:

Exactly max(N-1,0) comparisons, where N = std::distance(first, last).

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可能的实现

First version
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; }
Second version
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; }

为例

#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);
}

Output:

min element at: 1

另请参阅

max_element	返回最大的元素在一定范围内 Original: returns the largest element in a range The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. （函数模板）
minmax_element （C++11）	返回的最小和最大的元素在一定范围内 Original: returns the smallest and the largest element in a range The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. （函数模板）
min	返回两个元素的小 Original: returns the smaller of two elements The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. （函数模板）