[leetcode]Maximum Depth of Binary Tree @ Python

原題地址：https://oj.leetcode.com/problems/maximum-depth-of-binary-tree/

題意：

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.

解題思路：求樹的最大深度。使用遞歸，很簡單。

代碼：

# Definition for a  binary tree node
# class TreeNode:
#     def __init__(self, x):
#         self.val = x
#         self.left = None
#         self.right = None

class Solution:
    # @param root, a tree node
    # @return an integer
    def maxDepth(self, root):
        if root == None:
            return 0
        else:
            return max( self.maxDepth(root.left), self.maxDepth(root.right) ) + 1