Java 代码

import java.util.Scanner;public class Main {public static void main(String[] args) {Scanner sc = new Scanner(System.in);int n = sc.nextInt();char arr[][] = new char[n][3];for (int i = 0; i < n; i++) {String str=sc.next();char arr1[]=str.toCharArray();for (int j = 0; j < 3; j++) {arr[i][j]=arr1[j];}}TreeNode Root = null;Root = creat(arr, 0, 0);bianli(Root);}// 数据结构static class TreeNode {char val;public TreeNode left;public TreeNode right;public TreeNode(char val) {this.val = val;}}// 创建二叉树public static TreeNode creat(char arr[][], int i, int j) {if (i >= arr.length || j >= 3 ||arr[i][j] == '*') {return null;}TreeNode node = new TreeNode(arr[i][j]);for (int k = 0; k < arr.length; k++) {if(arr[i][j]==arr[k][0]){i=k;break;}}node.left = creat(arr, i, 1);node.right = creat(arr, i, 2);return node;}//遍历二叉树public static void bianli(TreeNode node){if (node==null) return;System.out.print(node.val);bianli(node.left);bianli(node.right);}
}

下面是失败的尝试

import java.util.Scanner;public class Main {public static void main(String[] args) {Scanner sc = new Scanner(System.in);int n = sc.nextInt();char arr[][] = new char[n][3];for (int i = 0; i < n; i++) {for (int j = 0; j < 3; j++) {arr[i][j] = sc.next().charAt(0);}}TreeNode Root = null;Root = creat(arr, 0, 0);bianli(Root);}// 数据结构static class TreeNode {char val;public TreeNode left;public TreeNode right;public TreeNode(char val) {this.val = val;}}// 创建二叉树public static TreeNode creat(char arr[][], int i, int j) {if (i >= arr.length || j >= 3 ||arr[i][j] == '*') {return null;}TreeNode node = new TreeNode(arr[i][j]);for (int k = 0; k < arr.length; k++) {if(arr[i][j]==arr[k][0]){i=k;break;}}node.left = creat(arr, i, 1);node.right = creat(arr, i, 2);return node;}//遍历二叉树public static void bianli(TreeNode node){if (node==null) return;System.out.print(node.val);bianli(node.left);bianli(node.right);}
}

紫色报错的原因：输入格式错了，输入的数据之间多加了空格分开。