Print in Reverse Hackerrank Solution - java

 Print in Reverse Hackerrank Solution - java

For Explanation Watch Video:

Code:

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 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) {

        while (node != null) {

            System.out.print(node.data);

            node = node.next;

            if (node != null) {

                System.out.print(sep);

            }

        }

    }

    public static void reversePrint(SinglyLinkedListNode llist) {

    // Write your code here

        ArrayList<Integer> al = new ArrayList<>();

        while(llist!=null){

            al.add(llist.data);

            llist = llist.next;

        }

        for(int i=al.size()-1;i>=0;i--){

            System.out.println(al.get(i));

        }

    }

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

    public static void main(String[] args) {

        int tests = scanner.nextInt();

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

        for (int testsItr = 0; testsItr < tests; testsItr++) {

            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])?");

                llist.insertNode(llistItem);

            }

            reversePrint(llist.head);

        }

        scanner.close();

    }

}