Create 40. Combination Sum II (#556)

Author: Chayandas07

40. Combination Sum II

@@ -0,0 +1,36 @@
+class Solution {
+public:
+    vector<vector<int>> combinationSum2(vector<int>& candidates, int target) {
+        sort(candidates.begin(), candidates.end());
+        vector<vector<int>> res;
+
+        vector<int> comb;
+        dfs(candidates, target, 0, comb, res);
+        return res;        
+    }
+
+    void dfs(vector<int>& candidates, int target, int start, vector<int>& comb, vector<vector<int>>& res) {
+        if (target < 0) {
+            return;
+        }
+    
+        if (target == 0) {
+            res.push_back(comb);
+            return;
+        }
+    
+        for (int i = start; i < candidates.size(); i++) {
+            if (i > start && candidates[i] == candidates[i-1]) {
+                continue;
+            }
+            
+            if (candidates[i] > target) {
+                break;
+            }
+            
+            comb.push_back(candidates[i]);
+            dfs(candidates, target - candidates[i], i + 1, comb, res);
+            comb.pop_back();
+        }
+    }
+};