秒杀

/** * Definition for binary tree * public class TreeNode { *     int val; *     TreeNode left; *     TreeNode right; *     TreeNode(int x) { val = x; } * } */public class Solution {    public int maxDepth(TreeNode root) {        if(root==null) return 0;      int h1=maxDepth(root.left);      int h2=maxDepth(root.right);      return h1>h2?h1+1:h2+1;            }}