cppreference.com > C++ Algorithms > partial_sort_copy partial_sort_copy Syntax:
      #include <algorithm>
      iterator partial_sort_copy( iterator start, iterator end, iterator result_start, iterator result_end );
      iterator partial_sort_copy( iterator start, iterator end, iterator result_start, iterator result_end, StrictWeakOrdering cmp );
The partial_sort_copy() algorithm behaves like partial_sort(), except that instead of partially sorting the range in-place, a copy of the range is created and the sorting takes place in the copy. The initial range is defined by [start,end) and the location of the copy is defined by [result_start,result_end). partial_sort_copy() returns an iterator to the end of the copied, partially-sorted range of elements. Related topics: binary_search is_sorted partial_sort sort stable_sort