104. 二叉树的最大深度

https://leetcode-cn.com/problems/maximum-depth-of-binary-tree/

Java

/*
 * @Author: Goog Tech
 * @Date: 2020-07-21 21:48:51
 * @Description: https://leetcode-cn.com/problems/maximum-depth-of-binary-tree/
 * @FilePath: \leetcode-googtech\#104. Maximum Depth of Binary Tree\Solution.java
 */ 

 /**
 * Definition for a binary tree node.
 * public class TreeNode {
 *     int val;
 *     TreeNode left;
 *     TreeNode right;
 *     TreeNode(int x) { val = x; }
 * }
 */

class Solution {
     // 后序遍历(DFS): 递归法
    public int maxDepth(TreeNode root) {
        return root == null ? 0 : Math.max(maxDepth(root.left),maxDepth(root.right)) + 1;
    }
}

Python

'''
@Author: Goog Tech
@Date: 2020-07-21 21:48:59
@Description: https://leetcode-cn.com/problems/maximum-depth-of-binary-tree/
@FilePath: \leetcode-googtech\#104. Maximum Depth of Binary Tree\Solution.py
'''
# 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):
    # 后序遍历(DFS): 递归法
    def maxDepth(self, root):
        """
        :type root: TreeNode
        :rtype: int
        """
        # lDepth = self.maxDepth(root.left)+1
        # rDepth = self.maxDepth(root.right)+1
        # return 0 if not root else lDepth if lDepth > rDepth else rDepth

        return 0 if not root else max(self.maxDepth(root.right),self.maxDepth(root.left)) + 1