【LeetCode】141. Linked List Cycle
正文
Difficulty:easy
More:【目录】LeetCode Java实现
Description
https://leetcode.com/problems/linked-list-cycle/
Given a linked list, determine if it has a cycle in it.
Follow up:
Can you solve it without using extra space?
Intuition
Use two pointers at different speed: the slow pointer moves one step at a time while the faster moves two steps at a time.
1) if the fast pointer meets the slow one, there is a cycle in the linked list;
2) if the fast pointer reaches the end(null), there is no cycle in the list.
Solution
1 2 3 4 5 6 7 8 9 10 11 12 13 | public boolean hasCycle(ListNode head) { if (head== null ) return false ; int fast=head; int slow=head; while (fast.next!= null && fast.next.next!= null ){ slow=slow.next; fast=fast.next.next; if (fast==slow) return true ; } return false ; } |
Complexity
Time complexity : O(n)
Space complexity : O(1)
What I've learned
1. Have a better understanding of the use of two pointers.
More:【目录】LeetCode Java实现
【推荐】编程新体验,更懂你的AI,立即体验豆包MarsCode编程助手
【推荐】凌霞软件回馈社区,博客园 & 1Panel & Halo 联合会员上线
【推荐】抖音旗下AI助手豆包,你的智能百科全书,全免费不限次数
【推荐】博客园社区专享云产品让利特惠,阿里云新客6.5折上折
【推荐】轻量又高性能的 SSH 工具 IShell:AI 加持,快人一步
· .NET Core 托管堆内存泄露/CPU异常的常见思路
· PostgreSQL 和 SQL Server 在统计信息维护中的关键差异
· C++代码改造为UTF-8编码问题的总结
· DeepSeek 解答了困扰我五年的技术问题
· 为什么说在企业级应用开发中,后端往往是效率杀手?
· 清华大学推出第四讲使用 DeepSeek + DeepResearch 让科研像聊天一样简单!
· 推荐几款开源且免费的 .NET MAUI 组件库
· 实操Deepseek接入个人知识库
· 易语言 —— 开山篇
· Trae初体验