题解 | #二叉树的最大深度#

# class TreeNode:
#     def __init__(self, x):
#         self.val = x
#         self.left = None
#         self.right = None
#
# 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
#
# 
# @param root TreeNode类 
# @return int整型
#
class Solution:
    def maxDepth(self , root: TreeNode) -> int:
        # write code here
        if not root:
            return 0
        depth = self.dfs(root, 0)
        return depth

    def dfs(self, root: TreeNode, depth: int):
        if root:
            depth += 1
            depth_l = self.dfs(root.left, depth)
            depth_r = self.dfs(root.right, depth)
            return max(depth_l, depth_r)
        else:
            return depth