class Solution { public: vector<vector<int>> res; vector<vector<int> > subsets(vector<int> &S) { vector<int> a; res.push_back(a); for(int i=1;i<=S.size();i++){ dfs(S,a,0,i); } return res; } void dfs(vector<int> &S,vector<int> a,int begin,int...