Create 078. Subsets.cpp

Author: fengvyi

C++/078. Subsets.cpp

@@ -0,0 +1,18 @@
+class Solution {
+public:
+    vector<vector<int>> subsets(vector<int>& nums) {
+        vector<vector<int>>res;
+        backtrack(nums, 0, vector<int>(), res);
+        return res;
+    }
+    
+    void backtrack(vector<int>& nums, int k, vector<int> subset, vector<vector<int>>& res){
+        if(k == nums.size()){
+            res.push_back(subset);
+            return;
+        }
+        backtrack(nums, k+1, subset, res);
+        subset.push_back(nums[k]);
+        backtrack(nums, k+1, subset, res);
+    }
+};