LeetCode Subsets

 1 class Solution {
 2 public:
 3     vector<vector<int> > subsets(vector<int> &S) {
 4         sort(S.begin(), S.end());
 5         vector<vector<int> > res;
 6         vector<int> path;
 7         dfs(S, path, 0, res);
 8         return res;
 9     }
10     
11     void dfs(vector<int>& s, vector<int>& cur, int pos, vector<vector<int> >& res) {
12         if (pos == s.size()) {
13             res.push_back(cur);
14             return;
15         }
16         // case 1. put the current number into the set
17         cur.push_back(s[pos]);
18         dfs(s, cur, pos + 1, res);
19         cur.pop_back();
20         
21         // case 2. skip the current number
22         dfs(s, cur, pos + 1, res);
23     }
24 };