Java Program To Add Two Numbers Represented By Linked Lists- Set 1

// Java program to add two numbers
// represented by linked list
class LinkedList 
{
    static Node head1, head2;

    static class Node 
    {
        int data;
        Node next;

        Node(int d)
        {
            data = d;
            next = null;
        }
    }

    /* Adds contents of two linked
       lists and return the head node
       of resultant list */
    Node addTwoLists(Node first, 
                     Node second)
    {
        // res is head node of the 
        // resultant list
        Node res = null;
        Node prev = null;
        Node temp = null;
        int carry = 0, sum;

        // while both lists exist
        while (first != null ||
               second != null) 
        {
            // Calculate value of next digit 
            // in resultant list. The next 
            // digit is sum of following things
            // (i)  Carry
            // (ii) Next digit of first
            // list (if there is a next digit)
            // (ii) Next digit of second
            // list (if there is a next digit)
            sum = carry + (first != null ? first.data : 0) + 
                  (second != null ? second.data : 0);

            // Update carry for next calculation
            carry = (sum >= 10) ? 1 : 0;

            // Update sum if it is greater 
            // than 10
            sum = sum % 10;

            // Create a new node with sum as data
            temp = new Node(sum);

            // if this is the first node then set
            // it as head of the resultant list
            if (res == null) 
            {
                res = temp;
            }

            // If this is not the first
            // node then connect it to the rest.
            else 
            {
                prev.next = temp;
            }

            // Set prev for next insertion
            prev = temp;

            // Move first and second pointers
            // to next nodes
            if (first != null) 
            {
                first = first.next;
            }
            if (second != null) 
            {
                second = second.next;
            }
        }

        if (carry > 0) 
        {
            temp.next = new Node(carry);
        }

        // return head of the resultant 
        // list
        return res;
    }

    /* Utility function to print a 
       linked list */
    void printList(Node head)
    {
        while (head != null) 
        {
            System.out.print(head.data + 
                             " ");
            head = head.next;
        }
        System.out.println("");
    }

    // Driver Code
    public static void main(String[] args)
    {
        LinkedList list = new LinkedList();

        // Creating first list
        list.head1 = new Node(7);
        list.head1.next = new Node(5);
        list.head1.next.next = new Node(9);
        list.head1.next.next.next = 
        new Node(4);
        list.head1.next.next.next.next =  
        new Node(6);
        System.out.print("First List is ");
        list.printList(head1);

        // Creating second list
        list.head2 = new Node(8);
        list.head2.next = new Node(4);
        System.out.print("Second List is ");
        list.printList(head2);

        // Add the two lists and see the result
        Node rs = list.addTwoLists(head1, head2);
        System.out.print("Resultant List is ");
        list.printList(rs);
    }
}
// This code is contributed by Mayank Jaiswal