2025-08-02 05:53:28 +0000 UTC

# 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 sumRootToLeaf(self, root: Optional[TreeNode]) -> int:
        def dfs(node: Optional[TreeNode], parent: int) -> int:
            if node is None:
                return 0
            cur_val = (parent << 1) | node.val
            if not node.left and not node.right:
                return cur_val
            return dfs(node.left, cur_val) + dfs(node.right, cur_val)
        return dfs(root, 0)