//If we need to add 2 integers, just reverse them and call them on addTwoNumbers()
//Similar to 369 Plus One Linked List
class Solution {
    public ListNode addTwoNumbers(ListNode l1, ListNode l2) {
        ListNode p1 = l1, p2 = l2, ans = new ListNode(0), p = ans;
        int carry = 0;
        while(p1 != null || p2 != null) {
            if(p1 != null) {
                carry += p1.val;
                p1 = p1.next;
            }
            if(p2 != null) {
                carry += p2.val;
                p2 = p2.next;
            }
            p.next = new ListNode(carry % 10);
            p = p.next;
            carry /= 10;
        }
        if(carry > 0) {
            p.next = new ListNode(carry);
        }
        return ans.next;
    }
}
/**
 * Definition for singly-linked list.
 * public class ListNode {
 *     int val;
 *     ListNode next;
 *     ListNode(int x) { val = x; }
 * }
 */