std::partition
From Cppreference
| Defined in header
<algorithm> | ||
| template< class ForwardIterator, class UnaryPredicate >
BidirectionalIterator partition( ForwardIterator first, ForwardIterator last, | ||
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 not preserved.
Contents |
Parameters
| first, last | - | the range of elements to reorder | |||||||||
| p | - | unary predicate which returns true if the element should be ordered before other elements. The signature of the predicate function should be equivalent to the following:
The signature does not need to have const &, but the function must not modify the objects passed to it. | |||||||||
Return value
iterator to the first element of the second group
Complexity
linear in the distance between first and last
Equivalent function
template<class BidirectionalIterator, class UnaryPredicate> BidirectionalIterator partition(BidirectionalIterator first, BidirectionalIterator last, UnaryPredicate p) { while (true) { while ((first != last) && p(*first)) { ++first; } if (first == last--) break; while ((first != last) && !p(*last)) { --last; } if (first == last) break; std::swap (*first++,*last); } return first; }
Example
| This section is incomplete |
See also
| divides elements into two groups while preserving their relative order (function template) | |
