加强基本功
class Solution { public: ListNode *addTwoNumbers(ListNode *l1, ListNode *l2) { ListNode *root = new ListNode(0); ListNode *p = root; int a = 0; while(l1 || l2){ int v1 = (l1 ? l1->val : 0); int v2 = (l2 ? l2->val : 0); int tmp = v1 + v2 + a; a = tmp /10; ListNode *pNode = new ListNode(tmp%10); p->next = pNode; p = p->next; if(l1) l1 = l1->next; if(l2) l2 = l2->next; } if(a > 0){ ListNode *pNode = new ListNode(a); p->next = pNode; } return root->next; } };