Print a singly linked list in spiral order

// C# code for the above approach:

using System;
using System.Collections.Generic;

class Node
{
    public int Data;
    public Node Next;

    public Node(int data)
    {
        Data = data;
        Next = null;
    }
}

class Program
{
    // Function to print the linked list in spiral order
    static void PrintInSpiralForm(Node head)
    {
        List<int> list = new List<int>();
        Node t = head;

        // Traversing the linked list and adding data to the list
        while (t != null)
        {
            list.Add(t.Data);
            t = t.Next;
        }

        int n = list.Count;
        int mid = (list.Count - 1) / 2;
        int left = mid;
        int right = mid + 1;

        // Keep two pointers, one at mid, and the other at next to mid
        while (left >= 0 || right < n)
        {
            if (left >= 0)
                Console.Write(list[left] + " -> ");
            if (right < n)
                Console.Write(list[right] + " -> ");
            left--;
            right++;
        }
        Console.WriteLine("X");
    }

    static void Main()
    {
        int[] arr = { 1, 2, 3, 4, 5, 6 };
        int n = arr.Length;
        Node root = null;

        // Create linked list from array
        for (int i = 0; i < n; i++)
        {
            Node newNode = new Node(arr[i]);
            if (root == null)
            {
                root = newNode;
            }
            else
            {
                Node ptr = root;
                while (ptr.Next != null)
                {
                    ptr = ptr.Next;
                }
                ptr.Next = newNode;
            }
        }

        // Call the function to print in spiral form
        PrintInSpiralForm(root);

        // Clean up memory (free nodes)
        while (root != null)
        {
            Node nextNode = root.Next;
            root.Next = null; // Release the node
            root = nextNode;
        }
    }
}

using System;

class Node
{
    public int Data { get; set; }
    public Node Next { get; set; }

    public Node(int data)
    {
        Data = data;
        Next = null;
    }
}

class LinkedList
{
    private Node Head { get; set; } // Points to the start of the linked list
    private Node Tail { get; set; } // Points to the end of the linked list

    // Get the head of the linked list
    public Node GetHead()
    {
        return Head;
    }

    // Find the middle node of the linked list using slow and fast pointers
    public Node GetMiddleOfList(Node head)
    {
        Node slow = head;
        Node fast = head;
        while (fast?.Next != null && fast.Next.Next != null)
        {
            slow = slow.Next;
            fast = fast.Next.Next;
        }
        return slow;
    }

    // Reverse the linked list from the head to the middle node
    public Node ReverseListTillMid(Node mid)
    {
        Node prev = null;
        Node current = Head;
        Node next = null;
        Node nextToMid = mid.Next;
        while (current != nextToMid)
        {
            next = current.Next;
            current.Next = prev;
            prev = current;
            current = next;
        }
        Head = prev;
        return nextToMid;
    }

    // Print two linked lists in a spiral form
    public void Print(Node head, Node secondHead)
    {
        Node itr1 = head;
        Node itr2 = secondHead;
        while (itr1 != null && itr2 != null)
        {
            Console.Write(itr1.Data + " -> ");
            Console.Write(itr2.Data + " -> ");
            itr1 = itr1.Next;
            itr2 = itr2.Next;
        }
        for (; itr1 != null; itr1 = itr1.Next)
        {
            Console.Write(itr1.Data + " -> ");
        }
        Console.WriteLine("X");
    }

    // Create a linked list from an array of integers
    public void CreateList(int[] data)
    {
        for (int i = 0; i < data.Length; i++)
        {
            if (Head == null)
            {
                Head = new Node(data[i]);
                Tail = Head;
            }
            else
            {
                Tail.Next = new Node(data[i]);
                Tail = Tail.Next;
            }
        }
    }

    // Print the linked list in a spiral form
    public void PrintInSpiralForm()
    {
        Node mid = GetMiddleOfList(Head); // Find the middle of the list
        Node nextToMid = ReverseListTillMid(mid); // Reverse the list till the middle
        Print(Head, nextToMid); // Print in a spiral form
    }
}

class Program
{
    static void Main()
    {
        int[] data = { 1, 2, 3, 4, 5, 6 };
        LinkedList list = new LinkedList();
        list.CreateList(data); // Create a linked list from the array
        Node head = list.GetHead(); // Get the head node
        list.PrintInSpiralForm(); // Print the linked list in spiral form

        // Clean up memory (free nodes)
        Node current = head;
        while (current != null)
        {
            current = current.Next; // No need for a temporary variable
        }
    }
}