题目链接：https://leetcode-cn.com/problems/fan-zhuan-lian-biao-lcof/
难度：简单

描述：
定义一个函数，输入一个链表的头节点，反转该链表并输出反转后链表的头节点。

题解

  1. # Definition for singly-linked list.
  2. # class ListNode:
  3. #     def __init__(self, x):
  4. #         self.val = x
  5. #         self.next = None
  7. class Solution:
  8.     def reverseList(self, head: ListNode) -> ListNode:
  9.         pre = None
  10.         cur = head
  12.         while cur is not None:
  13.             temp = cur
  14.             cur = cur.next
  15.             temp.next = pre
  16.             pre = temp
  18.         return pre