[LeetCode] Add Two Numbers

class Solution {
public:
ListNode *addTwoNumbers(ListNode *l1, ListNode *l2) {
ListNode *ret = new ListNode(0);
ListNode *cur = ret;
int sum = 0;
while (1) {
if (l1 != NULL) {
sum += l1->val;
l1 = l1->next;
}
if (l2 != NULL) {
sum += l2->val;
l2 = l2->next;
}
cur->val = sum % 10;
sum /= 10;
if (l1 != NULL || l2 != NULL || sum)
cur = (cur->next = new ListNode(0));
else
break;
}
return ret;
}
};