题解 | #链表内指定区间反转#

# class ListNode:
#     def __init__(self, x):
#         self.val = x
#         self.next = None
#
# 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
#
# 
# @param head ListNode类 
# @param m int整型 
# @param n int整型 
# @return ListNode类
#
class Solution:
    def reverseBetween(self , head: ListNode, m: int, n: int) -> ListNode:
        # write code here
        ans = ListNode(-1)
        ans.next = head
        pre = ans
        count = 0
        while count < m-1:
            count += 1
            pre = pre.next
        cur = pre.next
        while count < n-1:
            temp = cur.next
            cur.next = temp.next
            temp.next = pre.next
            pre.next = temp
            count += 1
        return ans.next

参考大神的代码，反转链表的部分是每次将当前节点的下一个节点放到最前面去，然后将当前节点与下一个节点的下一个节点相连