leetcode

0 class Solution {

1 ListNode *pre_mid(ListNode *head) {

2 ListNode *slow = head, *fast = head->next;

3 while (fast && fast->next && fast->next->next) {

4 slow = slow->next;

5 fast = fast->next->next;

6 }

7 return slow;

8 }

9

10 public:

11 ListNode *deleteMiddle(ListNode *head) {

12 if (!head || !head->next) return nullptr;

13 ListNode *pre = pre_mid(head);

14 pre->next = pre->next->next;

15 return head;

16 }

17 };