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;
}
};