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  1. #include <bits/stdc++.h>
  2. using namespace std;
  3.  
  4. void func(int idx, vector<int>& v, vector<vector<int>>& ans, vector<int>& temp) {
  5.     if (idx == (int)v.size()) {
  6.         ans.push_back(temp);
  7.         return;
  8.     }
  9.  
  10.     // Include current element
  11.     temp.push_back(v[idx]);
  12.     func(idx + 1, v, ans, temp);
  13.  
  14.     // Backtrack: remove the last element
  15.     temp.pop_back();
  16.  
  17.     // Exclude current element
  18.     func(idx + 1, v, ans, temp);
  19. }
  20.  
  21. int main() {
  22.     vector<int> v = {3, 1, 2};
  23.     vector<int> temp;
  24.     vector<vector<int>> ans;
  25.  
  26.     func(0, v, ans, temp);
  27.  
  28.     for (const auto& seq : ans) {
  29.         for (int num : seq)
  30.             cout << num << " ";
  31.         cout << endl;
  32.     }
  33. }
  34.  
Success #stdin #stdout 0.01s 5280KB
comments (?)
stdin
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Standard input is empty
stdout
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3 1 2 
3 1 
3 2 
3 
1 2 
1 
2
https://ideone.com/Y5xIfd
language:
C++ (gcc 8.3)
created:
6 days ago
visibility:
public

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