0078-subsets.cpp

/*
 Given an integer array of unique elements, return all possible subsets (the power set)
 Ex. nums = [1,2,3] -> [[],[1],[2],[1,2],[3],[1,3],[2,3],[1,2,3]]

 Backtracking, generate all combinations, push/pop + index checking to explore new combos

 Time: O(n x 2^n)
 Space: O(n)
*/

classSolution {
public:
 vector<vector<int>> subsets(vector<int>& nums) {
 vector<int> curr;
 vector<vector<int>> result;
dfs(nums, 0, curr, result);
return result;
 }
private:
voiddfs(vector<int>& nums, int start, vector<int>& curr, vector<vector<int>>& result) {
 result.push_back(curr);
for (int i = start; i < nums.size(); i++) {
 curr.push_back(nums[i]);
dfs(nums, i + 1, curr, result);
 curr.pop_back();
 }
 }
};