LeetCode-Add Two Numbers

You are given two linked lists representing two non-negative numbers. The digits are stored in reverse order and each of their nodes contain a single digit. Add the two numbers and return it as a linked list.

Input: (2 -> 4 -> 3) + (5 -> 6 -> 4)
Output: 7 -> 0 -> 8

Hide Tags Linked List Math

 1 /**
 2  * Definition for singly-linked list.
 3  * public class ListNode {
 4  *     int val;
 5  *     ListNode next;
 6  *     ListNode(int x) {
 7  *         val = x;
 8  *         next = null;
 9  *     }
10  * }
11  */
12 public class Solution {
13     public ListNode addTwoNumbers(ListNode l1, ListNode l2) {
14         if(l1==null && l2 == null){
15             return null;
16         }
17         else if(l1 != null && l2 == null){
18             return l1;
19         }
20         else if(l2 != null && l2 == null){
21             return l2;
22         }
23         
24         ListNode dummy = new ListNode(-1);
25         ListNode end = dummy;
26         int carry =0;
27         while(l1 != null || l2 != null || carry !=0){
28             int current =0;
29             if(l1 != null){
30                 current = current + l1.val;
31                 l1 = l1.next;
32             }
33             if(l2 != null){
34                 current = current +l2.val;
35                 l2 = l2.next;
36             }
37             if(carry !=0 ){
38                 current = current + carry;
39             }
40             
41             end.next = new ListNode(current%10);
42             carry = current / 10;
43             end = end.next;
44         }
45         return dummy.next;
46         
47     }
48 }