Question

compute the position of the last 5.0 in the list, counting as an offset from the end. if 5.0 is the LAST element, the position is 0. if 5.0 does not appear, return a negative number. you can write this using a loop or recursion, in any style, but you should only have one loop or recursive helper

Use a backward recursion.If the number does not appear, return the distance to the END of the list as a NEGATIVE number.

public class MyLinked {
   static class Node {
       public Node (double item, Node next) { this.item = item; this.next = next; }
       public double item;
       public Node next;
   }
   int N;

public int positionOfLastFiveFromEnd () {

You can NOT modify the list or parameters, add fields to the node or list class, or add any methods/use any functions to the node class. Please use a helper and backward recursion.

Answer 1

import java.io.*;
public class MyLinked {
public static Node head;
static class Node{
       public Node (double item, Node next)
        {
          this.item = item; this.next = next;
        }
       public double item;
       public Node next;}
   int N;

   public int positionOfLastFiveFromEnd ()
   {
            Node currNode = head;
        N=0;
          // Traverse through the LinkedList
       while (currNode!= null)
       { N-=1;
               // if currNode value is 5.0 then counter of
               // N will start from 0 again and will reach till
            if (currNode.item==5.0) {N=0;}
                // Go to next node
           currNode = currNode.next;
               }
        // last N's position will start from 0 ,
        //then it will be decremented by 1 until last node is reached.
       return( N);
  
       }
public static void main(String[] args)
    {
        /* Start with the empty list. */
   MyLinked list = new MyLinked();

  
       Node d=new Node (7,null); //making a last node with value equal to 5
   Node c=new Node(5,d); //making a node with value equal to 4
   Node b=new Node(3,c); //making a node with value equal to 3
   Node a=new Node(2,b); //making a node with value equal to 2
   head=a;
   int x =list.positionOfLastFiveFromEnd();// calling function
   System.out.print(x);
}
}