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  1.     #include <algorithm>
  2.     #include <iostream>
  3.     #include <iterator>
  4.     #include <random>
  5.     #include <vector>
  6.  
  7.     int main()
  8.     {
  9.     	// seed the RNG
  10.         std::random_device rd;
  11.         std::mt19937 mt(rd());
  12.  
  13.         std::vector<int> elements { 1, 2, 3, 4, 5, 6, 7, 8, 9 };
  14.  
  15.         std::cout << "Before: ";
  16.         std::copy(elements.cbegin(), elements.cend(),
  17.             std::ostream_iterator<int>(std::cout, " "));
  18.  
  19.         auto currentIndexCounter = elements.size();
  20.  
  21.         for (auto iter = elements.rbegin(); iter != elements.rend();
  22.             ++iter, --currentIndexCounter)
  23.         {
  24.         	// get int distribution with new range
  25.         	std::uniform_int_distribution<> dis(0, currentIndexCounter);
  26.             const int randomIndex = dis(mt);
  27.  
  28.             if (*iter != elements.at(randomIndex))
  29.             {
  30.                 std::swap(elements.at(randomIndex), *iter);
  31.             }
  32.         }
  33.  
  34.         std::cout << "\nAfter: ";
  35.         std::copy(elements.cbegin(), elements.cend(),
  36.             std::ostream_iterator<int>(std::cout, " "));
  37.     }
Success #stdin #stdout 0s 3472KB
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stdin
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Standard input is empty
stdout
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Before: 1 2 3 4 5 6 7 8 9 
After: 7 9 3 2 4 5 6 1 8
https://ideone.com/xVXeeN
language:
C++14 (gcc 8.3)
created:
7 years ago
visibility:
secret

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