[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

/** * Definition for singly-linked list. * public class ListNode { *     int val; *     ListNode next; *     ListNode(int x) { val = x; } * } */public class Solution {    public ListNode addTwoNumbers(ListNode l1, ListNode l2) {        ListNode head1 = l1;        ListNode head2 = l2;        int addOn = 0;        ListNode cur = null;        ListNode ansHead = null;        while(head1 != null || head2 != null || addOn != 0){            int value1 = 0;            int value2 = 0;            if(head1 != null){                value1 = head1.val;                head1 = head1.next;            }            if(head2 != null){                value2 = head2.val;                head2 = head2.next;            }             int result = value1+value2+addOn;            addOn = result / 10;            int nodeValue = result % 10;            ListNode newNode = new ListNode(nodeValue);            if(ansHead == null){                cur = newNode;                ansHead = newNode;            }            else{                cur.next = newNode;                cur = newNode;            }        }        return ansHead;    }}