class Solution {
public:
    ListNode* addTwoNumbers(ListNode* l1, ListNode* l2) {
    ListNode* res = new ListNode(-1);
    ListNode* r = res;
    int rem = 0;
    while(l1 && l2)
    {
        ListNode* aux = new ListNode((l1->val + l2->val + rem) % 10);
        r->next = aux;
        r = aux;
        rem = (l1->val + l2->val + rem) / 10;
        l1 = l1->next;
        l2 = l2->next;
    }
    while(l1)
    {
        ListNode* aux = new ListNode((l1->val + rem) % 10);
        r->next = aux;
        r = aux;
        rem = (l1->val + rem) / 10;
        l1 = l1->next;
    }
    while(l2)
    {
        ListNode* aux = new ListNode((l2->val + rem) % 10);
        r->next = aux;
        r = aux;
        rem = (l2->val + rem) / 10;
        l2 = l2->next;
    }
    if(rem)
    {
        ListNode* aux = new ListNode(rem);
        r->next = aux;
        r = aux;
    }
    return res->next;
    }
};