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  1. #include <algorithm>
  2. #include <cassert>
  3. #include <iostream>
  4. #include <iterator>
  5. #include <random>
  6. #include <vector>
  7.  
  8. // Fisher–Yates_shuffle
  9. std::vector<int> FisherYatesShuffle(std::size_t size, std::size_t max_size, std::mt19937& gen)
  10. {
  11.     assert(size < max_size);
  12.     std::vector<int> res(size);
  13.  
  14.     for(std::size_t i = 0; i != max_size; ++i) {
  15.         std::uniform_int_distribution<> dis(0, i);
  16.         std::size_t j = dis(gen);
  17.         if (j < res.size()) {
  18.             if (i < res.size()) {
  19.                 res[i] = res[j];
  20.             }
  21.             res[j] = i;
  22.         }
  23.     }
  24.     return res;
  25. }
  26.  
  27. int main()
  28. {
  29.     std::random_device rd;
  30.     std::mt19937 gen(rd());
  31.     std::vector<int> b = FisherYatesShuffle(5, 25, gen);
  32.  
  33.     std::copy(b.begin(), b.end(), std::ostream_iterator<int>(std::cout, " "));
  34.     return 0;
  35. }
  36.  
Success #stdin #stdout 0s 3432KB
comments (?)
stdin 
Standard input is empty
stdout 
6 10 18 17 9
https://ideone.com/KvvCda
language:
C++14 (gcc 8.3)
created:
11 years ago
visibility:
public

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