[LeetCode]206 反转链表

题目描述

反转一个单链表。

示例1:

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

示例2:

输入: s = "foo", t = "bar"
输出: false

代码

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# Definition for singly-linked list.
# class ListNode:
#     def __init__(self, x):
#         self.val = x
#         self.next = None

class Solution:
    def reverseList(self, head):
        """
        :type head: ListNode
        :rtype: ListNode
        """
        if not head:
            return None
        tmp=None
        while head:
            cur=head.next
            head.next=tmp
            tmp=head
            head=cur
        return tmp