LeetCode 104. Maximum Depth of Binary Tree

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.

public class Solution104 {    public static void main(String[] args) {        Solution104 solution104 = new Solution104();        TreeNode treeNode0 = new TreeNode(1);        TreeNode treeNode1 = new TreeNode(1);        TreeNode treeNode2 = new TreeNode(1);        TreeNode treeNode3 = new TreeNode(1);        TreeNode treeNode4 = new TreeNode(1);        treeNode0.left  = treeNode1;        treeNode0.right = treeNode2;        treeNode2.left  = treeNode3;        treeNode2.right = treeNode4;        int depth = solution104.maxDepth(treeNode0);        System.out.print(depth);    }    /**     * 我的做法,用递归实现,但是线上提交显示超时.     * 应该修改为注释的样子,用left,right保存     */    public int maxDepth(TreeNode root) {        if(root==null){            return 0;        }        if(1+maxDepth(root.left) > 1+maxDepth(root.right)){            return  1+maxDepth(root.left);        }else{            return  1+maxDepth(root.right);        }//        int left = 1+maxDepth(root.left);//        int right= 1+maxDepth(root.right);//        if(left > right){//            return  left;//        }else{//            return  right;//        }    }}class TreeNode {    int val;    TreeNode left;    TreeNode right;    TreeNode(int x) { val = x; }}