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  1. #include <iostream>
  2. #include <vector>
  3.  
  4.  
  5. std::uint16_t apply_filters(std::uint16_t init,
  6.                             const std::vector<std::uint16_t>& filters,
  7.                             const std::vector<bool>& mask)
  8. {
  9.     auto res = init;
  10.     for (std::size_t i = 0; i != filters.size(); ++i) {
  11.         if (mask[i]) {
  12.             res ^= filters[i];
  13.         }
  14.     }
  15.     return res;
  16. }
  17.  
  18. bool increase(std::vector<bool>& bs)
  19. {
  20.     for (std::size_t i = 0; i != bs.size(); ++i) {
  21.         bs[i] = !bs[i];
  22.         if (bs[i] == true) {
  23.             return true;
  24.         }
  25.     }
  26.     return false; // overflow
  27. }
  28.  
  29.  
  30. std::size_t count_filters_combination(std::uint16_t init,
  31.                                       const std::vector<std::uint16_t>& filters)
  32. {
  33.     std::vector<bool> bs(filters.size());
  34.  
  35.     std::size_t count = 0;
  36.     const std::uint16_t expected = 0b1111111111;
  37.     do
  38.     {
  39.         if (expected == apply_filters(init, filters, bs)) {
  40.             ++count;
  41.         }
  42.     } while (increase(bs));
  43.     return count;
  44. }
  45.  
  46.  
  47. int main()
  48. {
  49.     std::cout << count_filters_combination(0b1111111111, {0, 0}) << std::endl;
  50.     std::cout << count_filters_combination(0b0101010101, {0b1010101010, 0b1000000000, 0b0010101010}) << std::endl;
  51. }
  52.  
Success #stdin #stdout 0s 3460KB
comments (?)
stdin 
Standard input is empty
stdout 
4
2
https://ideone.com/TabjNq
language:
C++14 (gcc 8.3)
created:
8 years ago
visibility:
public

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