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std::partial_sort

From cppreference.com
< cpp‎ | algorithm
 
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Defined in header <algorithm>
template< class RandomIt >
void partial_sort( RandomIt first, RandomIt middle, RandomIt last );
 (1) (constexpr since C++20)
template< class ExecutionPolicy, class RandomIt >

void partial_sort( ExecutionPolicy&& policy,

                   RandomIt first, RandomIt middle, RandomIt last );
 (2) (since C++17)
template< class RandomIt, class Compare >

void partial_sort( RandomIt first, RandomIt middle, RandomIt last,

                   Compare comp );
 (3) (constexpr since C++20)
template< class ExecutionPolicy, class RandomIt, class Compare >

void partial_sort( ExecutionPolicy&& policy,
                   RandomIt first, RandomIt middle, RandomIt last,

                   Compare comp );
 (4) (since C++17)

Rearranges elements such that the range [first, middle) contains the sorted middle − first smallest elements in the range [first, last).

The order of equal elements is not guaranteed to be preserved. The order of the remaining elements in the range [middle, last) is unspecified.

1) Elements are sorted with respect to operator<(until C++20)std::less{}(since C++20).
3) Elements are sorted with respect to comp.
2,4) Same as (1,3), but executed according to policy.
These overloads participate in overload resolution only if all following conditions are satisfied:

std::is_execution_policy_v<std::decay_t<ExecutionPolicy>> is true.

(until C++20)

std::is_execution_policy_v<std::remove_cvref_t<ExecutionPolicy>> is true.

(since C++20)

If any of the following conditions is satisfied, the behavior is undefined:

  • [first, middle) or [middle, last) is not a valid range.
(until C++11)
(since C++11)

Contents

[edit] Parameters

first, last - the pair of iterators defining the