144.py

# 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 lcaDeepestLeaves(self, root: Optional[TreeNode]) -> Optional[TreeNode]:
        def dfs(root: TreeNode):
            if not root:
                return 0, None

            left = dfs(root.left)
            right = dfs(root.right)

            if left[0] > right[0]:
                return left[0] + 1, left[1]

            if left[0] < right[0]:
                return right[0] + 1, right[1]

            return left[0] + 1, root

        return dfs(root)[1]