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  1. #include <algorithm>
  2. #include <iostream>
  3. #include <vector>
  4.  
  5. template <typename T, typename F>
  6. void BreadthFirstCombination(const std::vector<T>& v, F f)
  7. {
  8.     for (int i = 0; i != v.size() + 1; ++i) {
  9.         std::vector<bool> mask(i, true);
  10.         mask.resize(v.size(), false);
  11.         do {
  12.             f(v, mask);
  13.         } while (std::prev_permutation(mask.begin(), mask.end()));
  14.     }
  15. }
  16.  
  17. int main() {
  18.  
  19.     auto printer = [](const auto&v, const std::vector<bool>& mask)
  20.     {
  21.         for (std::size_t i = 0; i != v.size(); ++i) {
  22.             if (mask[i]) {
  23.                 std::cout << v[i] << " ";
  24.             }
  25.         }
  26.         std::cout << std::endl;    
  27.     };
  28.     std::vector<int> v = {1, 2, 4};
  29.     BreadthFirstCombination(v, printer);
  30. }
  31.  
Success #stdin #stdout 0s 15240KB
comments (?)
stdin
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Standard input is empty
stdout
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1 
2 
4 
1 2 
1 4 
2 4 
1 2 4
https://ideone.com/J5uW39
language:
C++14 (gcc 8.3)
created:
8 years ago
visibility:
public

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