题解 | #二叉树的最大深度#

#     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:
        if root is None:return 0
        stack=[root]
        ceng=1
        while stack:
            for i in range(len(stack)):
                node=stack.pop(0)
                if node.left:
                    stack.append(node.left)
                if node.right:
                    stack.append(node.right)
            if len(stack)!=0:
                ceng+=1
        return ceng