Create: 0129-sum-root-to-leaf-numbers.py

python/0129-sum-root-to-leaf-numbers.py

@@ -0,0 +1,21 @@
+# Definition for a binary tree node.
+# class TreeNode:
+#     def __init__(self, val=0, left=None, right=None):
+#         self.val = val
+#         self.left = left
+#         self.right = right
+class Solution:
+    def sumNumbers(self, root: Optional[TreeNode]) -> int:
+
+        def dfs(node, res):
+            if not node:
+                return 0
+
+            res = res * 10 + node.val
+
+            if not node.left and not node.right:
+                return res
+
+            return dfs(node.left, res) + dfs(node.right, res)
+
+        return dfs(root, 0)