#include <algorithm>
#include <cassert>
#include <iostream>
#include <iterator>
#include <random>
#include <vector>

// Fisher–Yates_shuffle
std::vector<int> FisherYatesShuffle(std::size_t size, std::size_t max_size, std::mt19937& gen)
{
    assert(size < max_size);
    std::vector<int> res(size);

    for(std::size_t i = 0; i != max_size; ++i) {
        std::uniform_int_distribution<> dis(0, i);
        std::size_t j = dis(gen);
        if (j < res.size()) {
            if (i < res.size()) {
                res[i] = res[j];
            }
            res[j] = i;
        }
    }
    return res;
}

int main()
{
    std::random_device rd;
    std::mt19937 gen(rd());
    std::vector<int> b = FisherYatesShuffle(5, 25, gen);

    std::copy(b.begin(), b.end(), std::ostream_iterator<int>(std::cout, " "));
    return 0;
}