206. 反转链表

一、206. 反转链表 1.1、题目描述

1.2.1、迭代

class Solution:
    def reverseList(self, head: ListNode) -> ListNode:
        pre = None
        cur = head
        while cur:
            tmp = cur.next
            cur.next = pre
            pre = cur
            cur = tmp
        return pre