void subsetsUtils(int idx, vector<int> &S, vector<int> &solution, vector<vector<int> > &result) {

result.push_back(solution);

if(idx == S.size()) {

return;

}

for(int i = idx; i < S.size(); ++i) {

solution.push_back(S[i]);

subsetsUtils(i + 1, S, solution, result);

solution.pop_back();

}

}

vector<vector<int> > subsets(vector<int> &S) {

vector<vector<int> > result;

vector<int> solution;

if(S.size() < 0) return result;

subsetsUtils(0, S, solution, result);

return result;

}

void subsetsUtils(int idx, vector<int> &S, vector<int> &solution, vector<vector<int> > &result) {

if(idx == S.size()) {

result.push_back(solution);

return;

}

solution.push_back(S[idx]);

subsetsUtils(idx + 1, S, solution, result);

solution.pop_back();

subsetsUtils(idx + 1, S, solution, result);

}

vector<vector<int> > subsets(vector<int> &S) {

vector<vector<int> > result;

vector<int> solution;

if(S.size() < 0) return result;

subsetsUtils(0, S, solution, result);

return result;

}