78. Subsets

 1 class Solution {
 2 public:
 3     vector<vector<int>> subsets(vector<int>& nums) {
 4         sort(nums.begin(), nums.end());
 5         vector<int> path;
 6         vector<vector<int>> result;
 7         subsets(nums, path, 0, result);
 8         return result;
 9     }
10 private:
11     void subsets(const vector<int>& nums, vector<int>& path, int step, vector<vector<int>>& result) {
12         if (step == nums.size()) {
13             result.push_back(path);
14             return;
15         } else {
16             // no current element
17             subsets(nums, path, step + 1, result);
18             // add current element
19             path.push_back(nums[step]);
20             subsets(nums, path, step + 1, result);
21             path.pop_back();
22         }
23     }
24 };