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  1. #include <iostream>
  2. #include <algorithm>
  3.  
  4. template<typename T>
  5. void do_job(const std::vector<T>& v, const std::vector<std::size_t>& groups)
  6. {
  7.     std::cout << " e(";
  8.     for (std::size_t i = 0; i != v.size(); ++i) {
  9.         if (groups[i] == 0) {
  10.             std::cout << " " << v[i];
  11.         }
  12.     }
  13.     std::cout << ",";
  14.     for (std::size_t i = 0; i != v.size(); ++i) {
  15.         if (groups[i] == 1) {
  16.             std::cout << " " << v[i];
  17.         }
  18.     }
  19.     std::cout << ")\n";
  20. }
  21.  
  22. template<typename T>
  23. void print_combinations(const std::vector<T>& v)
  24. {
  25.     std::vector<std::size_t> groups(v.size() / 2, 0);
  26.     groups.resize(v.size(), 1);
  27.  
  28.     do {
  29.         do_job(v, groups);
  30.     } while (std::next_permutation(groups.begin(), groups.end()));
  31. }
  32.  
  33. int main()
  34. {
  35.     std::vector<int> numbers = {1, 2, 3, 4};
  36.     print_combinations(numbers);
  37. }
  38.  
Success #stdin #stdout 0s 3464KB
comments (?)
stdin 
Standard input is empty
stdout 
 e( 1 2, 3 4)
 e( 1 3, 2 4)
 e( 1 4, 2 3)
 e( 2 3, 1 4)
 e( 2 4, 1 3)
 e( 3 4, 1 2)
https://ideone.com/D2gphQ
language:
C++14 (gcc 8.3)
created:
10 years ago
visibility:
public

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