Nth_node_from_end_of_linked_list.java

// { Driver Code Starts
import java.util.*;
class Node
{
    int data;
    Node next;
    Node(int d) 
    {
        data = d; 
        next = null;
    }
}
    

    
public class LinkedList_Element_From_Last
{
    Node head;  
    Node tail;
    /* Function to print linked list */
    void printList(Node head)
    {
        Node temp = head;
        while (temp != null)
        {
            System.out.print(temp.data+" ");
            temp = temp.next;
        }  
        System.out.println();
    }
    
    
    /* Inserts a new Node at front of the list. */
    public void addToTheLast(Node node) 
    {

        if (head == null) 
        {
            head = node;
            tail = node;
        } else 
        {
            tail.next = node;
            tail = node;
        }
    }
        
        /* Drier program to test above functions */
    public static void main(String args[])
    {
            Scanner sc = new Scanner(System.in);
            int t=sc.nextInt();
            
            while(t>0)
            {
            int n = sc.nextInt();
            int k = sc.nextInt();
            LinkedList_Element_From_Last llist = new LinkedList_Element_From_Last();
            //int n=Integer.parseInt(br.readLine());
            int a1=sc.nextInt();
            Node head= new Node(a1);
            llist.addToTheLast(head);
            for (int i = 1; i < n; i++) 
            {
                int a = sc.nextInt(); 
                llist.addToTheLast(new Node(a));
            }
            
        //System.out.println(llist.head.data);
        GfG g = new GfG(); 
        //System.out.println(k);
        System.out.println(g.getNthFromLast(llist.head,k));
        
            t--;
        }
    }
}

class GfG{
    int getNthFromLast(Node head, int n){
        int count = 0;
        Node node = head;
        while(node != null){
            count++;
            node = node.next;
        }
        if( n > count ){
            return -1;
        }
        int s = count - n;
        for( int i = 0; i<s; i++ ){
            head = head.next;
        }
        return head.data;	
    }
}