shuffle.hpp

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#ifndef NEFORCE_CORE_ALGORITHM_SHUFFLE_HPP__
#define NEFORCE_CORE_ALGORITHM_SHUFFLE_HPP__

 
#include "NeForce/core/algorithm/shift.hpp"
#include "NeForce/core/numeric/random.hpp"
NEFORCE_BEGIN_NAMESPACE__



template <typename Iterator>
void shuffle(Iterator first, Iterator last) {
    static_assert(is_ranges_rnd_iter_v<Iterator>, "Iterators must be random_access_iterator");
 
    if (first == last) {
        return;
    }
    random_lcd rand;
    for (Iterator i = _NEFORCE next(first); i != last; ++i) {
        auto distance = _NEFORCE distance(first, i);
        Iterator j = _NEFORCE next(first, rand.next_int(0, static_cast<int>(distance)));
        _NEFORCE iter_swap(i, j);
    }
}

template <typename Iterator, typename Generator>
void shuffle(Iterator first, Iterator last, Generator& rand) {
    static_assert(is_ranges_rnd_iter_v<Iterator>, "Iterators must be random_access_iterator");
 
    if (first == last) {
        return;
    }
    for (Iterator i = _NEFORCE next(first); i != last; ++i) {
        Iterator j = _NEFORCE next(first, rand(i - first + 1));
        _NEFORCE iter_swap(i, j);
    }
}
 // ShuffleAlgorithms
 // StandardAlgorithms
 
NEFORCE_END_NAMESPACE__
#endif // NEFORCE_CORE_ALGORITHM_SHUFFLE_HPP__