leetcode - Subsets

class Solution {
public:
vector<vector<int> > subsets(vector<int> &S) {
// Note: The Solution object is instantiated only once and is reused by each test case.
sort(S.begin(), S.end());
int n = S.size();
vector<vector<int>> rlt;
rlt.push_back(vector<int>());
int i, j;
for (i=0; i<n; i++){
int m = rlt.size();
for (j=0; j<m; j++){
vector<int> tmp = rlt[j];
tmp.push_back(S[i]);
rlt.push_back(tmp);
}
}
return rlt;
}
};