| Defined in header <algorithm> | ||
|---|---|---|
template< class InputIt, class RandomIt >
RandomIt partial_sort_copy( InputIt first, InputIt last,
RandomIt d_first, RandomIt d_last ); | (1) | |
template< class InputIt, class RandomIt, class Compare >
RandomIt partial_sort_copy( InputIt first, InputIt last,
RandomIt d_first, RandomIt d_last,
Compare comp ); | (2) |
Sorts some of the elements in the range [first, last) in ascending order, storing the result in the range [d_first, d_last).
At most d_last - d_first of the elements are moved to the range [d_first, d_first + n) and then sorted. n is the number of elements to sort (n = min(last - first, d_last - d_first)). The order of equal elements is not guaranteed to be preserved. The first version uses operator< to compare the elements, the second version uses the given comparison function comp.
Parameters
| first, last | - | the range of elements to sort |
| d_first, d_last | - | random access iterators defining the destination range |
| comp | - | comparison function object (i.e. an object that satisfies the requirements of Compare) which returns true if the first argument is less than (i.e. is ordered before) the second. The signature of the comparison function should be equivalent to the following:
The signature does not need to have |
| Type requirements | ||
- InputIt must meet the requirements of InputIterator. | ||
- RandomIt must meet the requirements of ValueSwappable and RandomAccessIterator. | ||
-The type of dereferenced RandomIt must meet the requirements of MoveAssignable and MoveConstructible. | ||
Return value
an iterator to the element defining the upper boundary of the sorted range, i.e. d_first + min(last - first, d_last - d_first).
Complexity
O(N·log(min(D,N)), where N = std::distance(first, last), D = std::distance(d_first, d_last) applications of cmp.
Example
The following code sorts an vector of integers and copies them into a smaller and a larger vector.
#include <algorithm>
#include <vector>
#include <functional>
#include <iostream>
int main()
{
std::vector<int> v0{4, 2, 5, 1, 3};
std::vector<int> v1{10, 11, 12};
std::vector<int> v2{10, 11, 12, 13, 14, 15, 16};
std::vector<int>::iterator it;
it = std::partial_sort_copy(v0.begin(), v0.end(), v1.begin(), v1.end());
std::cout << "Writing to the smaller vector in ascending order gives: ";
for (int a : v1) {
std::cout << a << " ";
}
std::cout << '\n';
if(it == v1.end())
std::cout << "The return value is the end iterator\n";
it = std::partial_sort_copy(v0.begin(), v0.end(), v2.begin(), v2.end(),
std::greater<int>());
std::cout << "Writing to the larger vector in descending order gives: ";
for (int a : v2) {
std::cout << a << " ";
}
std::cout << '\n' << "The return value is the iterator to " << *it << '\n';
}Output:
Writing to the smaller vector in ascending order gives: 1 2 3 The return value is the end iterator Writing to the larger vector in descending order gives: 5 4 3 2 1 15 16 The return value is the iterator to 15
See also
| sorts the first N elements of a range (function template) | |
| sorts a range into ascending order (function template) | |
| sorts a range of elements while preserving order between equal elements (function template) | |
| std::experimental::parallel::partial_sort_copy
(parallelism TS) | parallelized version of std::partial_sort_copy (function template) |
Please login to continue.