```
vector<vector<int>> subsets(vector<int>& nums) {
sort(nums.begin(), nums.end());
vector<vector<int>> res;
vector<int> path;
dfs(nums, 0, path, res);
return res;
}
void dfs(vector<int>& nums, int index, vector<int>& path, vector<vector<int>>& res) {
res.push_back(path);
for (unsigned int i = index; i < nums.size(); i++) {
path.push_back(nums[i]);
dfs(nums, i+1, path, res);
path.pop_back();
}
}
```