nowcoder-python/BM/reverseBetween.py

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2022-03-01 16:48:48 +08:00
#!/usr/bin/env python3
# @author 轩辕龙儿
# @date 2022/3/1
# @file reverseBetween.py
# 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
#
from common import ListNode
class Solution:
def reverseBetween(self, head: ListNode, m: int, n: int) -> ListNode:
if m == n:
return head
pre = ListNode
cur = head
pre.next = cur
for i in range(m - 1):
pre = pre.next
cur = cur.next
for i in range(n - m):
nxt = cur.next
cur.next = nxt.next
nxt.next = pre.next
pre.next = nxt
if m == 1:
return pre.next
else:
return head