111. Minimum 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.

My code:

# 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 not root:
return 0
return max(self.maxDepth(root.left),self.maxDepth(root.right))+1

总结：要注意如果左右节点一个为空，要选大的。没有清楚概念，看了参考答案。但是思路和代码是对的。