39.Combination Sum

Author: ZQKC

39.Combination Sum.cpp

@@ -0,0 +1,28 @@
+class Solution {
+private:
+    void dfs(const vector<int> &candidates, int pos, int sum, int target, std::vector<int> &path, std::vector<std::vector<int>> &ans) {
+        if (sum == target) {
+            ans.push_back(path);
+            return ;
+        }
+        else if (sum > target) {
+            return ;
+        }
+        
+        for (int i = pos; i < candidates.size(); ++i) {
+            path.push_back(candidates[i]);
+            dfs(candidates, i, sum + candidates[i], target, path, ans);
+            path.pop_back();
+        }
+    }
+public:
+    vector<vector<int>> combinationSum(vector<int> candidates, int target) {
+        std::vector<std::vector<int>> ans;
+        std::vector<int> tmp;
+        
+        std::sort(candidates.begin(), candidates.end());
+        dfs(candidates, 0, 0, target, tmp, ans);
+        
+        return ans;
+    }
+};