这道题为简单题
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.
我是用递归做的，当然也可以用深搜和广搜，递归的话就是比较左右子树的深度然后返回
1 # Definition for a binary tree node. 2 # class TreeNode(object): 3 # def __init__(self, x): 4 # self.val = x 5 # self.left = None 6 # self.right = None 7 8 class Solution(object): 9 def maxDepth(self, root): 10 """ 11 :type root: TreeNode 12 :rtype: int 13 """ 14 if not root: return 0 15 16 left = self.maxDepth(root.left) 17 right = self.maxDepth(root.right) 18 if left > right: 19 return 1 + left 20 else: 21 return 1 + right
原文：http://www.cnblogs.com/liuxinzhi/p/7487447.html