acm模式Java输入传参二叉树（以层序遍历为例）

import java.util.*;

public class Tree {
   
   static class TreeNode{
   
      int val;
      TreeNode left;
      TreeNode right;
      public TreeNode(){
   }
      public TreeNode(int val){
   
         this.val = val;
      }
   }
	//方法入口
   public static void main(String[] args) {
   
      Scanner scanner = new Scanner(System.in);
      String s = scanner.nextLine();
      String[] split = s.split(" ");
      int[] arr = new int[split.length];
      for(int