reverse-a-linked-list_iterative.java

// { Driver Code Starts
import java.util.*;

class Node
{
    int data;
    Node next;
    Node(int d)
    { 
        data = d; 
        next = null;
    }
}

public class FindMiddle
{
    Node head;  // head of list
  public void addToTheLast(Node node) {

  if (head == null) {
   head = node;
  } else {
   Node temp = head;
   while (temp.next != null)
    temp = temp.next;

   temp.next = node;
  }
 }
	  
    public static void main(String args[])
    {
         Scanner sc = new Scanner(System.in);
		 int t=sc.nextInt();
		 
		 while(t>0)
         {
			int n = sc.nextInt();
			FindMiddle llist = new FindMiddle();
			//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));
			}
          
        GFG gfgobj = new GFG(); 
		//llist.head = new GFG().Middle(llist.head);
		System.out.println(gfgobj.getMiddle(llist.head));
        
		//llist.printList();
		
			t--;
		}
	}
}

// } Driver Code Ends
/* Node of a linked list
 class Node {
   int data;
    Node next;
    Node(int d)  { data = d;  next = null; }
}
 Linked List class
class LinkedList
{
    Node head;  // head of list
}
This is method only submission.  You only need to complete the method. */


class GFG
{
    // Function to find middle element a linked list
    int getMiddle(Node head)
   {
         Node slow = head;
         Node fast = head;
         while(fast.next != null && fast.next.next != null){
             slow = slow.next;
             fast = fast.next.next;
         }
         if(fast.next != null) slow = slow.next;
         return slow.data;
   }
}