using System;

​

public class ListNode{

    public int val;

    public ListNode(int v){

        val = v;

        next=null;

    }

    public ListNode next;

}

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Hello World");

        ListNode n1;

        ListNode node1 = new ListNode(4);

        n1 = node1;

        node1.next = new ListNode(8);

        node1 = node1.next;

        node1.next = new ListNode(10);

        ListNode n2;

        ListNode node2 = new ListNode(2);

        n2 = node2;

        node2.next = new ListNode(6);

        node2 = node2.next;

        node2.next = new ListNode(11);

        var retVal = MergeTwoSortedList(n1,n2);

​

        while(retVal!=null){

            Console.WriteLine(retVal.val);

            retVal = retVal.next;

        }

    }

    private static ListNode MergeTwoSortedList(ListNode n1,ListNode n2){

        ListNode retVal;

        if(n1==null && n2==null) return null;

        if(n1==null) return n2;

        if(n2==null) return n1;

        if(n1.val<n2.val){

            retVal = n1;

            n1.next = MergeTwoSortedList(n1.next,n2);

        }

        else{

            retVal = n2;

            n2.next = MergeTwoSortedList(n2.next,n1);

        }

        return retVal;

    }

}