std::random_shuffle, std::shuffle
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| Definido en el archivo de encabezado <algorithm>
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template< class RandomIt >
void random_shuffle( RandomIt first, RandomIt last );
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(1) | |
template< class RandomIt, class RandomFunc >
void random_shuffle( RandomIt first, RandomIt last, RandomFunc& r );
template< class RandomIt, class RandomFunc >
void random_shuffle( RandomIt first, RandomIt last, RandomFunc&& r );
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(2) | (hasta C++11) (desde C++11) |
template< class RandomIt, class URNG >
void shuffle( RandomIt first, RandomIt last, URNG&& g );
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(3) | (desde C++11) |
Reordena los elementos en el rango dado
[first, last) tales que cada permutacin posible de estos elementos tiene la misma probabilidad de aparicin .Original:
Reorders the elements in the given range
[first, last) such that each possible permutation of those elements has equal probability of appearance.The text has been machine-translated via Google Translate.
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1)
El generador de nmeros aleatorios es definido por la implementacin, pero el std::rand funcin se utiliza a menudo .
Original:
The random number generator is implementation-defined, but the function std::rand is often used.
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2)
El generador de nmeros aleatorios es el objeto de la funcin
r . Original:
The random number generator is the function object
r. The text has been machine-translated via Google Translate.
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3)
El generador de nmeros aleatorios es el objeto de la funcin
g .Original:
The random number generator is the function object
g.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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Parmetros
| first, last | - | la gama de elementos para barajar al azar
Original: the range of elements to shuffle randomly The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. |
| r | - | objeto de funcin que devuelve un valor escogido de forma aleatoria del tipo convertible a
iterator_traits<RandomIt>::difference_type en el intervalo [0, n) si se invoca como r(n) Original: function object returning a randomly chosen value of type convertible to iterator_traits<RandomIt>::difference_type in the interval [0,n) if invoked as r(n) The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. |
| g | - | objeto de funcin que devuelve un valor escogido de forma aleatoria de
URNG::result_type tipo en el intervalo [g.min (), g.max ()] si invoca como g() (por ejemplo, cualquiera de los generadores de nmeros aleatorios uniformes de <random>) Original: function object returning a randomly chosen value of type URNG::result_type in the interval [g.min(), g.max()] if invoked as g() (e.g. any of the uniform random number generators from <random>) The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. |
| Requisitos de tipo | ||
-RandomIt debe reunir los requerimientos de ValueSwappable y RandomAccessIterator.
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-URNG debe reunir los requerimientos de UniformRandomNumberGenerator.
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Valor de retorno
(Ninguno)
Original:
(none)
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Complejidad
lineal en la distancia entre
first y lastOriginal:
linear in the distance between
first and lastThe text has been machine-translated via Google Translate.
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Posible implementacin
| Primera versin |
|---|
template<class RandomIt, class RandomFunc>
void random_shuffle(RandomIt first, RandomIt last, RandomFunc&& r)
{
typename std::iterator_traits<RandomIt>::difference_type i, n;
n = last - first;
for (i = n-1; i > 0; --i) {
using std::swap;
swap(first[i], first[r(i+1)]);
}
}
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| Segunda versin |
template<class RandomIt, class UniformRandomNumberGenerator>
void shuffle(RandomIt first, RandomIt last,
UniformRandomNumberGenerator&& g)
{
typedef typename std::iterator_traits<RandomIt>::difference_type diff_t;
typedef typename std::make_unsigned<diff_t>::type udiff_t;
typedef typename std::uniform_int_distribution<udiff_t> distr_t;
typedef typename distr_t::param_type param_t;
distr_t D;
diff_t n = last - first;
for (diff_t i = n-1; i > 0; --i) {
using std::swap;
swap(first[i], first[D(g, param_t(0, i))]);
}
}
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Ejemplo
El cdigo siguiente cambia aleatoriamente los nmeros enteros 1 .. 10:
Original:
The following code randomly shuffles the integers 1..10:
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Ejecuta este cdigo
#include <random>
#include <algorithm>
#include <iterator>
#include <iostream>
int main()
{
std::vector<int> v = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
std::random_device rd;
std::mt19937 g(rd());
std::shuffle(v.begin(), v.end(), g);
copy(v.begin(), v.end(), std::ostream_iterator<int>(std::cout, " "));
std::cout << "\n";
}
Salida posible:
Original:
Possible output:
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8 6 10 4 2 3 7 1 9 5
Ver tambin
| Genera la siguiente permutacin lexicogrfica mayor de un rango de elementos. (plantilla de funcin) | |
| genera la siguiente permutacin lexicogrfica menor de un rango de elementos. (plantilla de funcin) |