104. Maximum Depth of Binary Tree

1/**
2 * Definition for a binary tree node.
3 * public class TreeNode {
4 *     int val;
5 *     TreeNode left;
6 *     TreeNode right;
7 *     TreeNode(int x) { val = x; }
8 * }
9 */
10class Solution {
11  
12    public int maxDepth(TreeNode root) {
13        if (root == null){
14            return 0;
15        }
16        
17        return 1 + Math.max(maxDepth(root.left), maxDepth(root.right));
18    }
19}

无脑DFS遍历左子树和右子树 然后比较左右哪个大