翻转链表思路

代码

class Solution {
    public ListNode reverseBetween(ListNode head, int m, int n) {

        ListNode dummy = new ListNode();
        dummy.next = head;

        ListNode a = dummy;
        for(int i = 0; i < m-1; i++) a = a.next;
        ListNode b = a.next, c = b.next;
        for(int i = 0; i < n-m; i++) {
            ListNode t = c.next;
            c.next = b;
            b = c; c = t;
        }

        a.next.next = c;
        a.next = b;

        return dummy.next;
    }
}