题解 | #链表内指定区间反转#

class Solution:
    def reverseBetween(self, head: ListNode, m: int, n: int) -> ListNode:
        if not ListNode or m == n:
            return head

        res = ListNode(0)
        res.next = head
        pre = res
        for _ in range(m-1):
            pre = pre.next
        cur = pre.next
        for _ in range(n-m):
            tmp = cur.next
            cur.next = tmp.next
            tmp.next = pre.next
            pre.next = tmp
        return res.next