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  1. #include <bits/stdc++.h>
  2. using namespace std;
  3. #define ll long long
  4. #define pb push_back
  5. #define nl '\n'
  6. #define py cout << "YES\n"
  7. #define pn cout << "NO\n"
  8. #define no_dup s.erase(unique(s.begin(), s.end()), s.end()); 
  9. const double eps = 1e-7;
  10.  
  11.  
  12. void fastio() {
  13.     ios_base::sync_with_stdio(false);
  14.     cin.tie(nullptr);
  15.     cout.tie(nullptr);
  16. }
  17.  
  18. //Generate all combinations use BackTrack Algorithm
  19. void generateBitStrings(int i, vector<int>& b, vector<vector<int>>& bitstrings) {
  20.     if (i == (int)b.size()) {
  21.         bitstrings.push_back(b);
  22.         return;
  23.     }
  24.     b[i] = 0;
  25.     generateBitStrings(i + 1, b, bitstrings);
  26.     b[i] = 1;
  27.     generateBitStrings(i + 1, b, bitstrings);
  28. }
  29.  
  30. void solve() {
  31.     set<char> charSet = {'A', 'B', 'C'};
  32.     vector<char> s(charSet.begin(), charSet.end());
  33.     int n = s.size();
  34.  
  35.     vector<int> b(n, 0);
  36.     vector<vector<int>> bitstrings;
  37.     generateBitStrings(0, b, bitstrings);
  38.  
  39.     vector<vector<char>> subsets;
  40.     for (const auto& bitstring : bitstrings) {
  41.         vector<char> subset;
  42.         for (int i = 0; i < n; i++) {
  43.             if (bitstring[i] == 1) {
  44.                 subset.push_back(s[i]);
  45.             }
  46.         }
  47.         subsets.push_back(subset);
  48.     }
  49.  
  50.     for (const auto& subset : subsets) {
  51.         if(subset.size()==0){
  52.             cout<<"empty set"<<nl;
  53.             continue;
  54.         }
  55.         for (char value : subset) {
  56.             cout << value << " ";
  57.         }
  58.         cout << nl;
  59.     }
  60. }
  61.  
  62. int main() {
  63.     fastio();
  64.     int t = 1;
  65.     //cin >> t;
  66.     while (t--)
  67.         solve();
  68.     return 0;
  69. }
Success #stdin #stdout 0.01s 5288KB
comments (?)
stdin 
Standard input is empty
stdout 
empty set
C 
B 
B C 
A 
A C 
A B 
A B C
https://ideone.com/r1Qx5o
language:
C++ (gcc 8.3)
created:
23 days ago
visibility:
public

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