1 class Solution: 2 ans = 0 3 def sumNumbers(self, root: TreeNode) -> int: 4 def dfs(root,n): 5 if not root:return 6 n *= 10 7 n += root.val 8 if not root.left and not root.right: 9 self.ans += n 10 return 11 dfs(root.left,n) 12 dfs(root.right,n) 13 dfs(root,0) 14 return self.ans