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:
    max = 0
    def maxDepth(self , root: TreeNode) -> int:
        # write code here
        if root == None:
            return  self.max
        def dfs(root, deep):
            if root == None:
                self.max = max(self.max, deep)
                return
            deep += 1
            dfs(root.left, deep)
            dfs(root.right, deep)
       
        dfs(root, 0)
        return self.max
	  
	  # 一行代码解决
	  def maxDepth(self , root: TreeNode) -> int:
        # write code here
		if not root:
		  return 0
		return 1+max(self.maxDepth(root.left),self.maxDepth(root.right))