LeetCode: Subsets

脑子有点混，少数次过

class Solution {
public:
    void dfs(int cur, int n, vector<vector<int>> &ret, vector<int> &tmp, vector<int> S) {
        if (cur == n) {
            ret.push_back(tmp);
            return;
        }
        dfs(cur+1, n, ret, tmp, S);
        tmp.push_back(S[cur]);
        dfs(cur+1, n, ret, tmp, S);
        tmp.pop_back();
    }
    vector<vector<int> > subsets(vector<int> &S) {
        // Start typing your C/C++ solution below
        // DO NOT write int main() function
        sort(S.begin(), S.end());
        vector<vector<int>> ret;
        if (!S.size()) return ret;
        vector<int> tmp;
        dfs(0, S.size(), ret, tmp, S);
        return ret;
    }
};

 C#

public class Solution {
    public List<List<int>> Subsets(int[] nums) {
        Array.Sort(nums);
        List<List<int>> ans = new List<List<int>>();
        if (nums.Length == 0) return ans;
        List<int> tmp = new List<int>();
        dfs(0, nums.Length, ref ans, ref tmp, nums);
        return ans;
    }
    public void dfs(int cur, int n, ref List<List<int>> ans, ref List<int> tmp, int[] nums) {
        if (cur == n) {
            ans.Add(new List<int>(tmp.ToArray()));
            return;
        }
        dfs(cur+1, n, ref ans, ref tmp, nums);
        tmp.Add(nums[cur]);
        dfs(cur+1, n, ref ans, ref tmp, nums);
        tmp.RemoveAt(tmp.Count - 1);
    }
}