addTwoNumbers

class Solution {
public:
    ListNode* addTwoNumbers(ListNode* l1, ListNode* l2) {
        ListNode preheader(-1), *curr=&preheader;
        int carry=0;
        while(l1||l2||carry) {
            curr->next = new ListNode(((l1?l1->val:0)+(l2?l2->val:0)+carry)%10);
            curr = curr->next;
            carry = ((l1?l1->val:0)+(l2?l2->val:0)+carry)/10;
            l1?l1=l1->next:0;
            l2?l2=l2->next:0;
        }
        return preheader.next;
    }
};