HackerRank中Compare Two LinkedList代码编译错误求助

问题描述 #

我编写了用于比较两个链表的Java代码，逻辑无误，但在HackerRank平台运行时持续出现编译错误，错误提示为“类、接口或枚举期望”相关报错。

错误代码 #

import java.io.*;
import java.math.*;
import java.text.*;
import java.util.*;
import java.util.regex.*;

public class Solution {

static class SinglyLinkedListNode {
    public int data;
    public SinglyLinkedListNode next;
    public SinglyLinkedListNode(int nodeData) {
        this.data = nodeData;
        this.next = null;
    }
}

static class SinglyLinkedList {
    public SinglyLinkedListNode head;
    public SinglyLinkedListNode tail;

    public SinglyLinkedList() {
        this.head = null;
        this.tail = null;
    }

    public void insertNode(int nodeData) {
        SinglyLinkedListNode node = new SinglyLinkedListNode(nodeData);

        if (this.head == null) {
            this.head = node;
        } else {
            this.tail.next = node;
        }

        this.tail = node;
    }
}

public static void printSinglyLinkedList(SinglyLinkedListNode node, String sep, BufferedWriter bufferedWriter) throws IOException {
    while (node != null) {
        bufferedWriter.write(String.valueOf(node.data));

        node = node.next;

        if (node != null) {
            bufferedWriter.write(sep);
        }
    }
}

// Complete the compareLists function below.

/*
 * For your reference:
 *
 * SinglyLinkedListNode {
 *     int data;
 *     SinglyLinkedListNode next;
 * }
 *
 */

static boolean compareLists(SinglyLinkedListNode head1, SinglyLinkedListNode head2) { 
    // while((head1 != null && head2 != null) && (head1.data == head2.data)){
    //     head1 = head1.next;
    //     head2 = head2.next;
    // }
    // return (head1 == null && head2 == null);
    
    // }
    
    while((head1!=null && head2!=null) && head1.data == head2.data){
        head1 = head1.next;
        head2 = head2.next;
    }
    return (head1 == null && head2 == null);

}
// 此处多余的}导致Solution类被提前闭合
}

错误信息 #

Solution.java:85: error: class, interface, or enum expected
    private static final Scanner scanner = new Scanner(System.in);
                         ^

Solution.java:87: error: class, interface, or enum expected
    public static void main(String[] args) throws IOException {
                  ^

Solution.java:90: error: class, interface, or enum expected
        int tests = scanner.nextInt();
        ^

Solution.java:91: error: class, interface, or enum expected
        scanner.skip("(\r\n|[\n\r\u2028\u2029\u0085])?");
        ^

Solution.java:93: error: class, interface, or enum expected
        for (int testsItr = 0; testsItr < tests; testsItr++) {
        ^

解决方案 #

问题根源是代码末尾添加了多余的}，导致Solution类被提前闭合。HackerRank平台会自动在用户提交的代码后追加scanner声明和main方法，这些代码必须位于Solution类内部才能通过编译。

修正方法：删除那个多余的}，让Solution类正确包含所有方法，平台自动生成的代码就能正常嵌入类中。

修正后的核心代码片段（完整代码仅需移除多余的闭合括号）：

// ... 前面的类和方法保持不变

static boolean compareLists(SinglyLinkedListNode head1, SinglyLinkedListNode head2) { 
    while((head1!=null && head2!=null) && head1.data == head2.data){
        head1 = head1.next;
        head2 = head2.next;
    }
    return (head1 == null && head2 == null);
}

// 此处不再保留多余的}，平台自动添加的代码将位于类内部

内容的提问来源于stack exchange，提问作者Satendra Patel