Java Program For Cloning A Linked List With Next And Random Pointer- Set 2

// Java program to clone a linked list 
// with random pointers
import java.util.HashMap;
import java.util.Map;

// Linked List Node class
class Node
{
    // Node data
    int data;

    // Next and random reference
    Node next, random;

    // Node constructor
    public Node(int data)
    {
        this.data = data;
        this.next = this.random = null;
    }
}

// Linked list class
class LinkedList
{
    // Linked list head reference
    Node head;

    // Linked list constructor
    public LinkedList(Node head)
    {
        this.head = head;
    }

    // Push method to put data always 
    // at the head in the linked list.
    public void push(int data)
    {
        Node node = new Node(data);
        node.next = this.head;
        this.head = node;
    }

    // Method to print the list.
    void print()
    {
        Node temp = head;
        while (temp != null)
        {
            Node random = temp.random;
            int randomData = ((random != null) ? 
                               random.data : -1);
            System.out.println("Data = " + temp.data + 
                               ", Random data = " + 
                               randomData);
            temp = temp.next;
        }
    }

    // Actual clone method which returns head
    // reference of cloned linked list.
    public LinkedList clone()
    {
        // Initialize two references, one with 
        // original list's head.
        Node origCurr = this.head, 
             cloneCurr = null;

        // Hash map which contains node to node 
        // mapping of original and clone linked list.
        Map<Node, Node> map = new HashMap<Node, Node>();

        // Traverse the original list and make a 
        // copy of that in the clone linked list.
        while (origCurr != null)
        {
            cloneCurr = new Node(origCurr.data);
            map.put(origCurr, cloneCurr);
            origCurr = origCurr.next;
        }

        // Adjusting the original list 
        // reference again.
        origCurr = this.head;

        // Traversal of original list again to 
        // adjust the next and random references 
        // of clone list using hash map.
        while (origCurr != null)
        {
            cloneCurr = map.get(origCurr);
            cloneCurr.next = 
            map.get(origCurr.next);
            cloneCurr.random = 
            map.get(origCurr.random);
            origCurr = origCurr.next;
        }

        // Return the head reference of the 
        // clone list.
        return new LinkedList(map.get(this.head));
    }
}

// Driver Class
class Main
{
    // Main method.
    public static void main(String[] args)
    {
        // Pushing data in the linked list.
        LinkedList list = 
        new LinkedList(new Node(5));
        list.push(4);
        list.push(3);
        list.push(2);
        list.push(1);

        // Setting up random references.
        list.head.random = 
        list.head.next.next;
        list.head.next.random =
        list.head.next.next.next;
        list.head.next.next.random =
        list.head.next.next.next.next;
        list.head.next.next.next.random =
        list.head.next.next.next.next.next;
        list.head.next.next.next.next.random =
        list.head.next;

        // Making a clone of the original 
        // linked list.
        LinkedList clone = list.clone();

        // Print the original and cloned 
        // linked list.
        System.out.println(
               "Original linked list");
        list.print();
        System.out.println(
               "Cloned linked list");
        clone.print();
    }
}