Objective: Given two polynomials, represent them by two linked lists and add these lists. java

// 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) { 
        Node res = null; // res is head node of the resultant list 
        Node prev = null; 
        Node temp = null; 
        int carry = 0, sum; 
  
        while (first != null || second != null) //while both lists exist 
        { 
            // 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 calulation 
            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; 
            } else // If this is not the first node then connect it to the rest. 
            { 
                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(""); 
    } 
  
    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 seconnd 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 has been contributed by Mayank Jaiswal