std::minmax_element
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<tbody> </tbody> template< class ForwardIt > std::pair<ForwardIt,ForwardIt> minmax_element( ForwardIt first, ForwardIt last ); |
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template< class ForwardIt, class Compare > std::pair<ForwardIt,ForwardIt> minmax_element( ForwardIt first, ForwardIt last, Compare comp ); |
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[first, last). operator< , comp.:
Finds the greatest and 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.| first, last | ||
| cmp | (.. , Compare), true, if *a is less than *b.:
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-ForwardIt ForwardIterator.
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, .
std::make_pair(first, first), . , , . , , .:
a pair consisting of an iterator to the smallest element as the first element and an iterator to the greatest element as the second. Returns
std::make_pair(first, first) if the range is empty. If several elements are equivalent to the smallest element, the iterator to the first such element is returned. If several elements are equivalent to the largest element, the iterator to the last such element is returned. max(floor(3/2(N1)), 0) ,
N = std::distance(first, last).:
At most max(floor(3/2(N1)), 0) applications of the predicate, where
N = std::distance(first, last).
template<class ForwardIt>
std::pair<ForwardIt, ForwardIt>
minmax_element(ForwardIt first, ForwardIt last)
{
typedef typename std::iterator_traits<ForwardIt>::value_type value_t;
return std::minmax_element(first, last, std::less<value_t>());
}
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template<class ForwardIt, class Compare>
std::pair<ForwardIt, ForwardIt>
minmax_element(ForwardIt first, ForwardIt last, Compare comp)
{
std::pair<ForwardIt, ForwardIt> result(first, first);
if (first == last) return result;
if (++first == last) return result;
if (comp(*first, *result.first)) {
result.second = result.first;
result.first = first;
} else {
result.second = first;
}
while (++first != last) {
ForwardIt i = first;
if (++first == last) {
if (comp(*i, *result.first)) result.first = i;
else if (!(comp(*i, *result.second))) result.second = i;
break;
} else {
if (comp(*first, *i)) {
if (comp(*first, *result.first)) result.first = first;
if (!(comp(*i, *result.second))) result.second = i;
} else {
if (comp(*i, *result.first)) result.first = i;
if (!(comp(*first, *result.second))) result.second = first;
}
}
}
return result;
}
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#include <algorithm>
#include <iostream>
#include <vector>
int main()
{
std::vector<int> v = { 3, 9, 1, 4, 2, 5, 9 };
auto result = std::minmax_element(v.begin(), v.end());
std::cout << "min element at: " << (result.first - v.begin()) << '\n';
std::cout << "max element at: " << (result.second - v.begin()) << '\n';
}
:
min element at: 2
max element at: 6
.
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