using System;

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Hello World");

        Node n = new Node(1);

        var two = n.Next = new Node(2);

        var three  = new Node(3);

        two.Next = three ;

        var four = new Node(4);

        three.Next = four;

        var five = new Node(5);

        four.Next = five;

        var six = new Node(6);

        five.Next = six;

        six.Next = five;

        //n.Next.Next = three;

        //three.Next = two;

        RemoveCycle(n);

        PrintLinkedList(n);

    }

    public static void RemoveCycle(Node head){

        if(head == null)

            return ;

        Node single = head.Next ;

        Node two = head.Next;

        Node beforeTwo = two;

        if(beforeTwo != null)

            two = beforeTwo.Next;

        else

            return;

        bool cycle = false;

        while(two != null)

        {

            if(two == single){

                //beforeTwo.Next = null;

                cycle = true;

                break;

            }

            single = single.Next;

            beforeTwo = two.Next;

            if(beforeTwo == null)

                return;

            else

                two = beforeTwo.Next;

        }

        if(!cycle)

            return;

        single = head;

        while(single != two){

            beforeTwo = two ;

            single = single.Next;

            two = beforeTwo.Next;

        }

        beforeTwo.Next = null;

    }

    public static void PrintLinkedList(Node head)

    {

        while(head != null)

        {

            Console.Write(head.Data + " " );

            head = head.Next ;

        }

    }

}

​

​

public class Node 

{

    public int Data { get;set;}

    public Node Next { get;set;}

    public Node(int d)

    {

        this.Data = d;

    }

}