Add C++ implementation

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

Author: begeekmyfriend

0129_sum_root_to_leaf_numbers/sum_tree.c

@@ -1,6 +1,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 
+
 struct TreeNode {
     int val;
     struct TreeNode *left;
@@ -9,12 +10,13 @@ struct TreeNode {
 
 static int dfs(struct TreeNode* node, int sum)
 {
-    int total = 0;
+    /* Here we have to use pre-order */
+    /* sum must be in argument stack of recusion.*/
     sum = sum * 10 + node->val;
-
     if (node->left == NULL && node->right == NULL) {
         return sum;
     } else {
+        int total = 0;
         if (node->left != NULL) {
             total += dfs(node->left, sum);
         }
@@ -25,7 +27,7 @@ static int dfs(struct TreeNode* node, int sum)
     }
 }
 
-static int sumNumbers(struct TreeNode* root)
+int sumNumbers(struct TreeNode* root)
 {
     if (root == NULL) {
         return 0;

0129_sum_root_to_leaf_numbers/sum_tree.cc

@@ -0,0 +1,42 @@
+#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:
+    int sumNumbers(TreeNode* root) {
+        if (root == nullptr) {
+            return 0;
+        }
+        return dfs(root, 0);
+    }
+private:
+    int dfs(TreeNode *root, int sum) {
+        // Here we have to use pre-order.
+        // sum must be in argument stack of recusion.
+        sum = sum * 10 + root->val;
+        if (root->left == nullptr && root->right == nullptr) {
+            return sum;
+        } else {
+            int total = 0;
+            if (root->left != nullptr) {
+                total += dfs(root->left, sum);
+            }
+            if (root->right != nullptr) {
+                total += dfs(root->right, sum);
+            }
+            return total;
+        }
+    }
+};