std::stable_partition (3) - Linux Manuals
Defined in header <algorithm>
template< class BidirIt, class UnaryPredicate > (1)
BidirIt stable_partition( BidirIt first, BidirIt last, UnaryPredicate p );
template< class ExecutionPolicy, class BidirIt, class UnaryPredicate > (2) (since C++17)
BidirIt stable_partition( ExecutionPolicy&& policy, BidirIt first, BidirIt last, UnaryPredicate p );
1) Reorders the elements in the range [first, last) in such a way that all elements for which the predicate p returns true precede the elements for which predicate p returns false. Relative order of the elements is preserved.
2) Same as (1), but executed according to policy. This overload only participates in overload resolution if std::is_execution_policy_v<std::decay_t<ExecutionPolicy>> is true.
first, last - the range of elements to reorder
policy - the execution policy to use. See execution_policy for details.
p - The expression p(v) must be convertible to bool for every argument v of type (possibly const) VT, where VT is the value type of BidirIt, regardless of value_category, and must not modify v. Thus, a parameter type of VT&is not allowed
BidirIt must meet the requirements of ValueSwappable and LegacyBidirectionalIterator.
The type of dereferenced BidirIt must meet the requirements of MoveAssignable and MoveConstructible.
UnaryPredicate must meet the requirements of Predicate.
Iterator to the first element of the second group
Given N = last - first
1) Exactly N applications of the predicate and O(N) swaps if there is enough extra memory. If memory is insufficient, at most N log N swaps.
2) O(N log N) swaps and O(N) applications of the predicate
The overload with a template parameter named ExecutionPolicy reports errors as follows:
* If execution of a function invoked as part of the algorithm throws an exception and ExecutionPolicy is one of the standard_policies, std::terminate is called. For any other ExecutionPolicy, the behavior is implementation-defined.
* If the algorithm fails to allocate memory, std::bad_alloc is thrown.
This function attempts to allocate a temporary buffer. If the allocation fails, the less efficient algorithm is chosen.
// Run this code
partition (function template)