问题描述：

反转一个单链表。

示例:

输入: 1->2->3->4->5->NULL输出: 5->4->3->2->1->NULL

方法1：头插法

1 class Solution(object): 2     def reverseList(self, head): 3         """ 4         :type head: ListNode 5         :rtype: ListNode 6         """ 7         dummy = ListNode(-1) 8         if head == None: 9             return []10         if head.next == None:11             return head12         p = head.next13         while p != None:14             p = head.next15             head.next = dummy.next16             dummy.next = head17             head = p18         return dummy.next

2018-09-18 21:17:27