3Sum is a high-frequency interview question. The core approach is sorting + two pointers. Problem Given , find all unique triplets that sum to 0. Answer: . Solution Evolution Brute […]
System Design Interview Guide: Designing a Short URL Service (TinyURL)
Designing a short URL service is a classic system desig […]
HTTP and HTTPS Interview Guide: Status Codes, Caching, TLS Handshake
The HTTP protocol is a fundamental topic in backend int […]
Doris vs ClickHouse: A Comparative Study of OLAP Databases
I've been studying OLAP databases recently and put toge […]
My Terminal Toolchain: 2025 Development Efficiency Suite
Let me share the terminal tools I use frequently in my […]
LeetCode 146. LRU Cache: The Interviewer's Favorite Design Problem — Hand-Writing a Doubly Linked List + Hash Map
The LRU Cache is one of the most frequently asked desig […]
MySQL Transaction Isolation Levels Explained for Interviews: How to Distinguish Dirty Reads, Phantom Reads, and Non-Repeatable Reads?
Transaction isolation levels are almost a guaranteed qu […]
PostgreSQL or MySQL? Rethinking Database Selection in 2025
The debate between MySQL and PostgreSQL has never stopp […]
The Three Generations of Distributed Locks: From Redis to Etcd to Lock-Free Design
Distributed locks may seem simple, but they are full of […]
TCP Three-Way Handshake and Four-Way Wave: What Do Interviewers Really Want to Hear?
TCP connection establishment and teardown is a core top […]