문제 난이도 : Easy

문제 유형 : Data Structures - Linked Lists

문제 설명 간략 :

LinkedList head에 node를 삽입하라.

제약사항

• 1 <= n <= 1000
• 1 <= list[i] <= 1000

자바 풀이

import java.io.*;
import java.math.*;
import java.security.*;
import java.text.*;
import java.util.*;
import java.util.concurrent.*;
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 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 insertNodeAtHead function below.

    /*
     * For your reference:
     *
     * SinglyLinkedListNode {
     *     int data;
     *     SinglyLinkedListNode next;
     * }
     *
     */
    static SinglyLinkedListNode insertNodeAtHead(SinglyLinkedListNode llist, int data) {
        SinglyLinkedListNode node = new SinglyLinkedListNode(data);
        if (llist == null) {
            return node;
        }

        node.next = llist;
        return node;
    }

    private static final Scanner scanner = new Scanner(System.in);

    public static void main(String[] args) throws IOException {
        BufferedWriter bufferedWriter = new BufferedWriter(new FileWriter(System.getenv("OUTPUT_PATH")));

        SinglyLinkedList llist = new SinglyLinkedList();

        int llistCount = scanner.nextInt();
        scanner.skip("(\r\n|[\n\r\u2028\u2029\u0085])?");

        for (int i = 0; i < llistCount; i++) {
            int llistItem = scanner.nextInt();
            scanner.skip("(\r\n|[\n\r\u2028\u2029\u0085])?");

            SinglyLinkedListNode llist_head = insertNodeAtHead(llist.head, llistItem);

            llist.head = llist_head;
        }



        printSinglyLinkedList(llist.head, "\n", bufferedWriter);
        bufferedWriter.newLine();

        bufferedWriter.close();

        scanner.close();
    }
}

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