AddLinkedList.java

class Solution {
 public ListNode addTwoNumbers(ListNode l1, ListNode l2) {
 ListNode dummy = new ListNode(); 
 ListNode temp = dummy; 
 int carry = 0;
 while( l1 != null || l2 != null || carry == 1) {
 int sum = 0; 
 if(l1 != null) {
 sum += l1.val; 
 l1 = l1.next; 
 }
 
 if(l2 != null) {
 sum += l2.val; 
 l2 = l2.next; 
 }
 
 sum += carry; 
 carry = sum / 10; 
 ListNode node = new ListNode(sum % 10); 
 temp.next = node; 
 temp = temp.next; 
 }
 return dummy.next;
 }
}