using System;

​

public class Program

{

    public static void Main(string[] args)

    {

        var first = new Node(1);

        var second = new Node(2);

        var third = new Node(3);

        var fourth = new Node(4);

        var fifth = new Node(5);

        var sixth = new Node(6);

        first.Next = second;

        second.Next = third;

        third.Next = fourth;

        fourth.Next = fifth;

        fifth.Next = sixth;

        first.Print();

        Reverse(ref first);

        Console.WriteLine("=============== After swapping ===============");

        first.Print();

    }

​

    static void Reverse(ref Node head)

    {

        if (head == null)

        {

            return;

        }

​

        var first = head;

        var rest = head.Next;

        if (rest == null)

        {

            return;

        }

​

        Reverse(ref rest);

        first.Next.Next = first;

        first.Next = null;

        head = rest;

    }

}

​

public class Node

{

    public int Data

    {

        get;

        set;

    }

​

    public Node Next

    {

        get;

        set;

    }

​

    public Node(int data)

    {

        this.Data = data;

        this.Next = null;

    }

​

    public void Print()

    {

        var node = this;

        do

        {

            Console.WriteLine(node.Data);

            node = node.Next;

        }

        while (node != null);

    }

​

    public int GetLengthIterative()

    {

        var node = this;

        var count = 0;

        while (node != null)

        {

            count++;

            node = node.Next;

        }

​

        return count;

    }

​

    public int GetLengthRecursive()

    {

        if (this.Next == null)

        {

            return 1;

        }

​

        return 1 + this.Next.GetLengthRecursive();

    }

​

    public override string ToString()

    {

        return Data.ToString();

    }

}