addTwoNumbers

 1 class Solution {
 2 public:
 3     ListNode* addTwoNumbers(ListNode* l1, ListNode* l2) {
 4         ListNode preheader(-1), *curr=&preheader;
 5         int carry=0;
 6         while(l1||l2||carry) {
 7             curr->next = new ListNode(((l1?l1->val:0)+(l2?l2->val:0)+carry)%10);
 8             curr = curr->next;
 9             carry = ((l1?l1->val:0)+(l2?l2->val:0)+carry)/10;
10             l1?l1=l1->next:0;
11             l2?l2=l2->next:0;
12         }
13         return preheader.next;
14     }
15 };