题目来源
https://leetcode.com/problems/maximum-depth-of-binary-tree/
Given a binary tree, find its maximum depth.
The maximum depth is the number of nodes along the longest path from the root node down to the farthest leaf node.
题意分析
Input: tree
Output: int
Conditions:给定一个二叉树，返回最大深度
题目思路
递归遍历即可
AC代码（Python）
# Definition for a binary tree node.
# class TreeNode(object):
# def __init__(self, x):
# self.val = x
# self.left = None
# self.right = None class Solution(object):
def maxDepth(self, root):
"""
:type root: TreeNode
:rtype: int
"""
if root == None:
return 0
else:
return max(self.maxDepth(root.left), self.maxDepth(root.right)) + 1