[LeetCode] 78. Subsets

Given a set of distinct integers, S, return all possible subsets.

Note:

• Elements in a subset must be in non-descending order.
• The solution set must not contain duplicate subsets.

 

For example,
If S = [1,2,3], a solution is:

[
  [3],
  [1],
  [2],
  [1,2,3],
  [1,3],
  [2,3],
  [1,2],
  []
]

 

class Solution {
public:
    vector > subsets(vector &S) {
        vector > res;
        vector out;
        sort(S.begin(), S.end());
        getSubsets(S, 0, out, res);
        return res;
    }
    void getSubsets(vector &S, int pos, vector &out, vector > &res) {
        res.push_back(out);
        for (int i = pos; i < S.size(); ++i) {
            out.push_back(S[i]);
            getSubsets(S, i + 1, out, res);
            out.pop_back();
        }
    }
};