LeetCode小白菜笔记[19]：Maximum Depth of Binary Tree

LeetCode小白菜笔记[19]：Maximum Depth of Binary Tree

104. Maximum Depth of Binary Tree [easy]

由于编号失误，居然漏了一个19，在这里补充上。

题目：

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.

For example:
Given binary tree [3,9,20,null,null,15,7],

    3
   / 
  9  20
    /  
   15   7

return its depth = 3.

这个题目很简单，就是求二叉树的深度。深度是二叉树的一个属性，一个递归就可以解决，不再赘述。

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

53ms，62.86%

2018年2月13日23:07:17

one hour before Valentine‘s Day ^_^