Leetcode 2 Add Two Numbers Java

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

342+465=801

public class Solution {    public ListNode addTwoNumbers(ListNode l1, ListNode l2) {        ListNode preHead=new ListNode(-1);        ListNode pre=preHead;        int carry=0;        while(l1!=null||l2!=null){            int v1=(l1==null?0:l1.val);            int v2=(l2==null?0:l2.val);            int curSum=v1+v2+carry;            carry=curSum/10;            pre.next=new ListNode(curSum%10);            l1=(l1==null?null:l1.next);            l2=(l2==null?null:l2.next);            pre=pre.next;        }        if(carry!=0){            pre.next=new ListNode(carry);        }        return preHead.next;    }}