Low-Level Design: Parking Lot System (OOP Interview)
Problem Statement Design an object-oriented parking lot system. The lot has multiple levels, each with multiple spots of different sizes […]
System Design
System Design
System Design Interview: Design a Leaderboard / Top-K System
System Design: Top-K / Leaderboard (Heavy Hitters) Top-K problems appear in many real-world systems: game leaderboards, trending hashtags, most-viewed videos,
System Design
Low-Level Design: Logging Framework (OOP Interview)
Low-Level Design: Logging Framework A logging framework is a fundamental software engineering tool — and a frequently-asked OOP design question
System Design
System Design Interview: Design a Geo-Proximity Service (Yelp / Nearby)
System Design: Geo-Proximity Service (Yelp / Google Maps Nearby) A geo-proximity service finds places (restaurants, drivers, stores) near a given
System Design
Low-Level Design: Notification System (OOP Interview)
Low-Level Design: Notification System A notification system delivers messages to users via multiple channels (push, email, SMS, in-app). It must
System Design
System Design Interview: Design a Distributed Search Engine
System Design: Distributed Search Engine A distributed search engine indexes documents and serves queries with sub-100ms latency at massive scale.
System Design
Low-Level Design: Task Scheduler / Job Queue (OOP Interview)
Low-Level Design: Task Scheduler / Job Queue A task scheduler executes jobs at specified times or with specified delays, tracks
Algorithms
Union-Find (DSU) Interview Patterns (2025)
Union-Find (Disjoint Set Union) Interview Patterns Union-Find (DSU) solves the dynamic connectivity problem: given a graph where edges are added
System Design
Low-Level Design: Pub/Sub Event System (OOP Interview)
Low-Level Design: Pub/Sub Event System The Publish-Subscribe pattern is one of the most important OOP design patterns. It decouples event
System Design
System Design Interview: Design a Distributed Message Queue (Kafka)
System Design: Distributed Message Queue (Kafka) A distributed message queue decouples producers (services that generate events) from consumers (services that
System Design
Low-Level Design: Online Shopping Cart (OOP Interview)
Low-Level Design: Online Shopping Cart The online shopping cart is a fundamental e-commerce OOP design problem. It tests entity modeling
Algorithms
Interval Algorithm Interview Patterns (2025)
Interval Algorithm Patterns Interval problems appear constantly in coding interviews — at Google, Meta, Airbnb, and Uber. The key skill:
System Design
System Design Interview: Design a Social Media News Feed
System Design: News Feed (Facebook / Instagram / Twitter) A social media news feed aggregates posts from a user’s network
Algorithms
Dynamic Programming on Strings: LCS, Edit Distance, and Patterns (2025)
Dynamic Programming on Strings String DP problems are among the most common in technical interviews, especially at Meta, Amazon, and
System Design
Low-Level Design: Elevator System (OOP Interview)
Low-Level Design: Elevator System The elevator system is a classic OOP interview problem testing state machines, dispatching algorithms, and clean