题目描述

blablabla

样例

blablabla

算法1

() $O(n^2)$

blablabla

时间复杂度分析：blablabla

Python 代码

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

class Solution(object):
    def reverseList(self, head):
        """
        :type head: ListNode
        :rtype: ListNode
        """
        if head is None or head.next is None:
            return head
        cur = None
        while head:
            tmp = head.next # 保存当前节点下一节点 可能为0 所以最后head会move到0 返回cur
            head.next = cur # 指向上一个循环的节点
            cur = head # 保存目前节点
            head = tmp # head指针往下移动
        return cur