std::partial_sort
Defined in header <algorithm>
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template< class RandomIt > void partial_sort( RandomIt first, RandomIt middle, RandomIt last ); |
(1) | |
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) | |
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.
operator<
.comp
.policy
. These overloads do not participate in overload resolution unless std::is_execution_policy_v<std::decay_t<ExecutionPolicy>> is trueParameters
first, last | - | the range of elements to sort |
policy | - | the execution policy to use. See execution policy for details. |
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: bool cmp(const Type1 &a, const Type2 &b); The signature does not need to have const &, but the function object must not modify the objects passed to it. |
Type requirements | ||
-RandomIt must meet the requirements of ValueSwappable and RandomAccessIterator .
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-The type of dereferenced RandomIt must meet the requirements of MoveAssignable and MoveConstructible .
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Return value
(none)
Complexity
Approximately (last-first)log(middle-first)) applications of cmp
Exceptions
The overloads with a template parameter named ExecutionPolicy
report errors as follows:
- If execution of a function invoked as part of the algorithm throws an exception and
ExecutionPolicy
is one of the three standard policies, std::terminate is called. For any otherExecutionPolicy
, the behavior is implementation-defined. - If the algorithm fails to allocate memory, std::bad_alloc is thrown.
Example
#include <algorithm> #include <functional> #include <array> #include <iostream> int main() { std::array<int, 10> s{5, 7, 4, 2, 8, 6, 1, 9, 0, 3}; std::partial_sort(s.begin(), s.begin() + 3, s.end()); for (int a : s) { std::cout << a << " "; } }
Possible output:
0 1 2 7 8 6 5 9 4 3
See also
partially sorts the given range making sure that it is partitioned by the given element (function template) | |
copies and partially sorts a range of elements (function template) | |
sorts a range of elements while preserving order between equal elements (function template) | |
sorts a range into ascending order (function template) |