leetcode

0 class Solution {

1 public:

2 ListNode *swapPairs(ListNode *head) {

3 ListNode *d = new ListNode(-1, head);

4 for (ListNode *p = d; p->next && p->next->next;) {

5 ListNode *t = p->next;

6 p->next = p->next->next;

7 t->next = p->next->next;

8 p->next->next = t;

9 p = t;

10 }

11 return d->next;

12 }

13 };