using System.Collections.Generic;
using System.Linq;

namespace JonsAnswers
{
    class LinkedListNode
    {
        public LinkedListNode Next { get; set; }
        public LinkedListNode Other { get; set; }
        public string Value { get; set; }
    }

    class Program
    {
        static LinkedListNode GenerateSpecialLinkedList()
        {
            LinkedListNode root = new LinkedListNode();
            LinkedListNode itemOne = new LinkedListNode();
            LinkedListNode itemTwo = new LinkedListNode();
            LinkedListNode itemThree = new LinkedListNode();
            LinkedListNode itemFour = new LinkedListNode();

            root.Next = itemOne;
            itemOne.Next = itemTwo;
            itemTwo.Next = itemThree;
            itemThree.Next = itemFour;
            itemFour.Next = null;

            root.Value = "I";
            itemOne.Value = "Formed";
            itemTwo.Value = "A";
            itemThree.Value = "Sentence";
            itemFour.Value = "Here.";

            root.Other = itemThree;
            itemOne.Other = itemOne;
            itemTwo.Other = root;
            itemThree.Other = itemFour;
            itemFour.Other = itemTwo;

            return root;
        }

        static LinkedListNode ReturnCopy(LinkedListNode list)
        {
            List<LinkedListNode> nodeList = new List<LinkedListNode>();

            LinkedListNode root = list;

            while (true)
            {
                nodeList.Add(root);

                root = root.Next;

                if (root == null)
                    break;
            }

            // Weirdly named I know.
            List<int> referenceFlags = nodeList.Select(node => nodeList.IndexOf(node.Other)).ToList();

            List<LinkedListNode> newNodeList = new List<LinkedListNode>();
            newNodeList.AddRange(from x in Enumerable.Range(0, nodeList.Count) select new LinkedListNode());

            for (int i = 0; i < nodeList.Count; i++)
            {
                newNodeList[i].Other = newNodeList[referenceFlags[i]];
                newNodeList[i].Value = nodeList[i].Value;

                if (i == nodeList.Count - 1)
                    break;

                newNodeList[i].Next = newNodeList[i + 1];
            }

            return newNodeList.First();
        }

        static void Main(string[] args)
        {
            LinkedListNode root = GenerateSpecialLinkedList();
            LinkedListNode copy = ReturnCopy(root);
        }
    }
}