【刷题记录 python】反转链表

Q(n)时间，O(1)空间
关键点：
（1）初始化：pre为None，cur指向链表头节点
（2)cur.next指向pre，pre每次更新为调整指向后的cur
(3)temp记录调整指向前的cur.next
(4)终止条件cur已经为None

# -*- coding:utf-8 -*-
# class ListNode:
#     def __init__(self, x):
#         self.val = x
#         self.next = None
class Solution:
    # 返回ListNode
    def ReverseList(self, pHead):
        # write code here
        pre = None
        cur = pHead
        while cur:
            temp = cur.next
            cur.next = pre
            pre = cur
            cur = temp
        return pre