Intersection of Two Linked Lists Java

PROGRAM TO GET THE  INTERSECTION POINT OF TWO LINKED LISTS

class LinkedList {

 

    static Node head1, head2;

 

    static class Node {

 

        int data;

        Node next;

 

        Node(int d)

        {

            data = d;

            next = null;

        }

    }

 

    /*function to get the intersection point of two linked

    lists head1 and head2 */

    int getNode()

    {

        int c1 = getCount(head1);

        int c2 = getCount(head2);

        int d;

 

        if (c1 > c2) {

            d = c1 - c2;

            return _getIntesectionNode(d, head1, head2);

        }

        else {

            d = c2 - c1;

            return _getIntesectionNode(d, head2, head1);

        }

    }

 

    /* function to get the intersection point of two linked

     lists head1 and head2 where head1 has d more nodes than

     head2 */

    int _getIntesectionNode(int d, Node node1, Node node2)

    {

        int i;

        Node current1 = node1;

        Node current2 = node2;

        for (i = 0; i < d; i++) {

            if (current1 == null) {

                return -1;

            }

            current1 = current1.next;

        }

        while (current1 != null && current2 != null) {

            if (current1.data == current2.data) {

                return current1.data;

            }

            current1 = current1.next;

            current2 = current2.next;

        }

 

        return -1;

    }

 

    /*Takes head pointer of the linked list and

    returns the count of nodes in the list */

    int getCount(Node node)

    {

        Node current = node;

        int count = 0;

 

        while (current != null) {

            count++;

            current = current.next;

        }

 

        return count;

    }

 

    public static void main(String[] args)

    {

        LinkedList list = new LinkedList();

 

        // creating first linked list

        list.head1 = new Node(3);

        list.head1.next = new Node(6);

        list.head1.next.next = new Node(9);

        list.head1.next.next.next = new Node(15);

        list.head1.next.next.next.next = new Node(30);

 

        // creating second linked list

        list.head2 = new Node(10);

        list.head2.next = new Node(15);

        list.head2.next.next = new Node(30);

 

        System.out.println("The node of intersection is " + list.getNode());

    }

}

OUTPUT

The node of intersection is 15

CREDITS: https://www.geeksforgeeks.org/write-a-function-to-get-the-intersection-point-of-two-linked-lists/