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partial_sort_copy
function template
<algorithm>
template <class InputIterator, class RandomAccessIterator>
RandomAccessIterator
partial_sort_copy ( InputIterator first,InputIterator last,
RandomAccessIterator result_first,
RandomAccessIterator result_last );
template <class InputIterator, class RandomAccessIterator, class Compare>
RandomAccessIterator
partial_sort_copy ( InputIterator first,InputIterator last,
RandomAccessIterator result_first,
RandomAccessIterator result_last, Compare comp );
Copy and partially sort range
Copies the smallest elements in the range [first,last) to [result_first,result_last), sorting the elements copied. The amount of elements copied is (result_last-result_first) (unless this is more than the amount of elements in [first,last)).
[first,last) remains unmodified.
The elements are compared using operator< for the first version, and comp for the second.
Parameters
- first, last
- Input iterators to the initial and final positions of the sequence to copy from. The range used is [first,last), which contains all the elements between first and last, including the element pointed by first but not the element pointed by last.
- result_first, result_last
- Random-Access iterators to the initial and final positions of the destination sequence. The range used is [result_first,result_last).
- comp
- Comparison function object that, taking two values of the same type than those contained in the range, returns true if the first argument goes before the second argument in the specific strict weak ordering it defines, and false otherwise.
Return value
none
Example
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// partial_sort_copy example
#include <iostream>
#include <algorithm>
#include <vector>
using namespace std;
bool myfunction (int i,int j) { return (i<j); }
int main () {
int myints[] = {9,8,7,6,5,4,3,2,1};
vector<int> myvector (5);
vector<int>::iterator it;
// using default comparison (operator <):
partial_sort_copy (myints, myints+9, myvector.begin(), myvector.end());
// using function as comp
partial_sort_copy (myints, myints+9, myvector.begin(), myvector.end(), myfunction);
// print out content:
cout << "myvector contains:";
for (it=myvector.begin(); it!=myvector.end(); ++it)
cout << " " << *it;
cout << endl;
return 0;
}
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Output:
myvector contains: 1 2 3 4 5
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Complexity
Performs approximately N*log(N2) comparisons, where N is the length of [first,last) and N2 is the length of the shortests between [first,last) and [result_first,result_last).
See also
| partial_sort | Partially Sort elements in range (function template) |
| sort | Sort elements in range (function template) |
| copy | Copy range of elements (function template) |
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