#include <vector>
class Solution {
public:
    void dfs(vector<vector<int>> & ans, vector<int> &temp, vector<int> S, int n, int start){
        ans.push_back(temp);
        for(int i = start; i < n; i++){
            temp.push_back(S[i]);
            dfs(ans, temp, S, n, i + 1);
            temp.pop_back();
        }
    }
    vector<vector<int> > subsets(vector<int>& S) {
        // write code here
        vector<int> temp;
        vector<vector<int>> ans;
        
        int n = S.size();

        dfs(ans, temp, S, n, 0);
        return ans;
    }
};