LeetCode – Refresh – Subsets

Classical combination problem.

class Solution {
public:
    void getComb(vector<vector<int> > &result, vector<int> &num, vector<int> current, int index, int len) {
        if (current.size() == len) {
            result.push_back(current);
            return;
        }
        for (int i = index; i < num.size(); i++) {
            current.push_back(num[i]);
            getComb(result, num, current, i+1, len);
            current.pop_back();
        }
    }
    vector<vector<int> > subsets(vector<int> &S) {
        vector<vector<int> > result;
        sort(S.begin(), S.end());
        for (int i = 0; i <= S.size(); i++) {
            getComb(result, S, vector<int>(), 0, i);
        }
        return result;
    }
};