std::stable_partition
Defined in header
<algorithm>
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template< class BidirIt, class UnaryPredicate >
BidirIt stable_partition( BidirIt first, BidirIt last, UnaryPredicate p ); |
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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.
Contents |
[edit] 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: bool pred(const Type &a); The signature does not need to have const &, but the function must not modify the objects passed to it. |
Type requirements | ||
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BidirIt must meet the requirements of ValueSwappable and BidirectionalIterator .
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-The type of dereferenced BidirIt must meet the requirements of MoveAssignable and MoveConstructible .
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UnaryPredicate must meet the requirements of Predicate .
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[edit] Return value
Iterator to the first element of the second group
[edit] Complexity
Exactly last-first
applications of the predicate and at most (last-first)*log(last-first)
swaps if there is insufficient memory or linear number of swaps if sufficient memory is available.
[edit] Notes
This function attempts to allocate a temporary buffer, typically by calling std::get_temporary_buffer. If the allocation fails, the less efficient algorithm is chosen.
[edit] Example
#include <iostream> #include <algorithm> #include <vector> int main() { std::vector<int> v{0, 0, 3, 0, 2, 4, 5, 0, 7}; std::stable_partition(v.begin(), v.end(), [](int n){return n>0;}); for (int n : v) { std::cout << n << ' '; } std::cout << '\n'; }
Output:
3 2 4 5 7 0 0 0 0
[edit] See also
divides a range of elements into two groups (function template) |
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(parallelism TS)
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parallelized version of std::stable_partition (function template) |