#!/user/bin/env python

# coding=utf-8

"""

@project : algorithmPython

@ide : PyCharm

@file : reverseBetween

@author : illusion

@desc : 92. 反转链表 II https://leetcode-cn.com/problems/reverse-linked-list-ii/

@create : 2020-10-25 17:28:10

"""

from listNode.model import ListNode

class Solution:

def reverseBetween(self, head: ListNode, m: int, n: int) -> ListNode:

newHead = ListNode(-1)

newHead.next = head

begin = newHead # m-1 处

# 遍历到逆转的起来

i = 1

while i < m:

begin, i = begin.next, i + 1

cur = begin.next

start = begin.next # m 处

pre = None

while i <= n:

tp, cur.next = cur.next, pre

pre, cur, i = cur, tp, i + 1

begin.next = pre

if start:

start.next = cur

return newHead.next

s = Solution()

n5 = ListNode(5)

n4 = ListNode(4)

n4.next = n5

n3 = ListNode(3)

n3.next = n4

n2 = ListNode(2)

n2.next = n3

n1 = ListNode(1)

n1.next = n2

s = Solution()

r: list = s.reverseBetween(n1, 2, 4)

string = "["

if r:

string += str(r.val)

r = r.next

while r:

string += f", {r.val}"

r = r.next

string += ']'

print(string)