Add C++ implementation

Signed-off-by: begeekmyfriend <[email protected]>

Author: begeekmyfriend

0113_path_sum_ii/path_sum.cc

@@ -0,0 +1,39 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+/**
+ * Definition for a binary tree node.
+ * struct TreeNode {
+ *     int val;
+ *     TreeNode *left;
+ *     TreeNode *right;
+ *     TreeNode() : val(0), left(nullptr), right(nullptr) {}
+ *     TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
+ *     TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
+ * };
+ */
+class Solution {
+public:
+    vector<vector<int>> pathSum(TreeNode* root, int targetSum) {
+        vector<vector<int>> res;
+        dfs(root, targetSum, res);
+        return res;
+    }
+private:
+    vector<int> stack;
+    void dfs(TreeNode* root, int sum, vector<vector<int>>& res) {
+        if (root == nullptr) {
+            return;
+        } else if (root->left == nullptr && root->right == nullptr && sum == root->val) {
+            stack.push_back(root->val);
+            res.push_back(stack);
+            stack.pop_back();
+        } else {
+            stack.push_back(root->val);
+            dfs(root->left, sum - root->val, res);
+            dfs(root->right, sum - root->val, res);
+            stack.pop_back();
+        }
+    }
+};