[Leetcode] 002. Add Two Numbers

https://leetcode.com/problems/add-two-numbers/

public class Solution {
    public ListNode addTwoNumbers(ListNode l1, ListNode l2) {
        if(l1 == null) return l2;
        if(l2 == null) return l1;
    
        ListNode head = new ListNode(0);
        ListNode p = head;
        
        int tmp = 0;
        while(l1!=null || l2!=null || tmp!=0) {
            if(l1!=null){
                tmp += l1.val;
                l1 = l1.next;
            }
            if(l2!=null){
                tmp += l2.val;
                l2 = l2.next;
            }
            p.next = new ListNode(tmp%10);
            p = p.next;
            tmp = tmp/10;
        }
        return head.next;
    }
}