[LeetCode] Subsets

class Solution {public:    vector<vector<int> > result;    void dfs(vector<int> &num,int deep,int maxDeep,vector<int> a,int start){        result.push_back(a);        if(deep == maxDeep) return;        for(int i = start;i < num.size();i ++){            vector<int>b(a);            b.push_back(num[i]);            dfs(num,deep + 1,maxDeep,b,i + 1);        }    }    vector<vector<int> > subsets(vector<int> &S) {        sort(S.begin() , S.end());        vector<int> a;        dfs(S,0,S.size(),a,0);        return result;    }};