Max Depth of Binary Tree

题目描述

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.

解题方法

recursion,因为是取最大值，所以在当前node为None时可以直接返回0

Solution

# 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 1 + max(self.maxDepth(root.left), self.maxDepth(root.right))

Reference