std::partition
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| Defined in header <algorithm>
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| template< class BidirIt, class UnaryPredicate > BidirectionalIterator partition( BidirIt first, BidirIt last, |
(hasta C++11) (desde C++11) |
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Reordena los elementos de la
[first, last) rango de tal manera que todos los elementos para los que el predicado p vuelve true preceder a los elementos para los que predicado p vuelve false. Orden relativo de los elementos no se conserva . Original:
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. The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.
You can help to correct and verify the translation. Click here for instructions.
Contenido |
[editar] Parámetros
| first, last | - | la gama de elementos a ordenar
Original: the range of elements to reorder The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. |
| p | - | unary predicate which returns true si el elemento debe pedirse antes de otros elementos . Original: if the element should be ordered before other elements The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. 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 | ||
-BidirIt must meet the requirements of BidirectionalIterator.
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-ForwardIt must meet the requirements of ValueSwappable and ForwardIterator. However, the operation is more efficient if ForwardIt also satisfies the requirements of BidirectionalIterator
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[editar] Valor de retorno
Iterador al primer elemento del segundo grupo .
Original:
Iterator to the first element of the second group.
The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.
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[editar] Complejidad
Exactamente last-first aplicaciones del predicado y en la mayoría de los swaps last-first. Si
ForwardIt cumple los requisitos de BidirectionalIterator en la mayoría de los swaps (last-first)/2 se hacen .Original:
Exactly last-first applications of the predicate and at most last-first swaps. If
ForwardIt meets the requirements of BidirectionalIterator at most (last-first)/2 swaps are done.The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.
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[editar] Posible implementación
template<class BidirIt, class UnaryPredicate> BidirIt partition(BidirIt first, BidirIt last, UnaryPredicate p) { while (1) { 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; } |
[editar] Ejemplo
#include <algorithm> #include <functional> #include <iostream> #include <iterator> #include <vector> bool is_even(int i) { return i % 2 == 0; } int main() { std::vector<int> v; for (int i = 0; i < 10; ++i) v.push_back(i); std::cout << "Original vector:\n "; std::copy(v.begin(), v.end(), std::ostream_iterator<int>(std::cout, " ")); // Partition the vector std::vector<int>::iterator p = std::partition(v.begin(), v.end(), std::ptr_fun(is_even)); std::cout << "\nPartitioned vector:\n "; std::copy(v.begin(), v.end(), std::ostream_iterator<int>(std::cout, " ")); std::cout << "\nBefore partition:\n "; std::copy(v.begin(), p, std::ostream_iterator<int>(std::cout, " ")); std::cout << "\nAfter partition:\n "; std::copy(p, v.end(), std::ostream_iterator<int>(std::cout, " ")); }
Possible output:
Original vector:
0 1 2 3 4 5 6 7 8 9
Partitioned vector:
0 8 2 6 4 5 3 7 1 9
Before partition:
0 8 2 6 4
After partition:
5 3 7 1 9[editar] Ver también
| (C++11) |
determina si el intervalo está dividido por el predicado dado Original: determines if the range is partitioned by the given predicate The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (función de plantilla) |
| elementos divide en dos grupos, preservando su orden relativo Original: divides elements into two groups while preserving their relative order The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (función de plantilla) | |
