Union-Find (Disjoint Set Union) Interview Patterns
What Is Union-Find? Union-Find (also called Disjoint Set Union or DSU) is a data structure that efficiently tracks which elements […]
Algorithms
Algorithms
Binary Tree Interview Patterns: Traversal, DFS, BFS, and Classic Problems
Tree Traversal Fundamentals Binary tree problems appear in nearly every technical interview. The foundation is traversal order, which determines which
System Design
System Design Interview: Real-Time Chat System (WhatsApp / Slack)
Core Requirements A real-time chat system must: deliver messages in under 100ms end-to-end, support 1:1 and group chats, handle offline
System Design
System Design Interview: File Storage and Sync Service (Dropbox)
Designing a file storage and sync service like Dropbox combines chunked file storage, delta sync, conflict resolution, and offline-first architecture.
Algorithms
String DP Interview Patterns: LCS, Edit Distance, Palindrome DP
String dynamic programming problems — longest common subsequence, edit distance, palindromic subsequences — appear frequently in senior engineering interviews. These
System Design
System Design Interview: Twitter / Social Media Feed Architecture
Designing a social media feed like Twitter is one of the most comprehensive system design problems. The core challenge: how
System Design
System Design Interview: Hotel and Airbnb Booking System
Designing a hotel or home-sharing booking system like Airbnb is a comprehensive system design problem that combines availability calendars, concurrent
System Design
System Design Interview: Video Streaming Platform (Netflix/YouTube)
Designing a video streaming platform like Netflix or YouTube is one of the most comprehensive system design challenges, combining video
Algorithms
Dynamic Programming Knapsack Patterns: 0/1, Unbounded, Subset Sum
Knapsack problems are the most important dynamic programming pattern class. Mastering 0/1 knapsack, unbounded knapsack, and their variants (subset sum,
System Design
System Design Interview: Email Service at Scale (SendGrid/Gmail)
Designing a transactional email service (like SendGrid or AWS SES) or an email client (like Gmail) involves deep distributed systems
System Design
System Design Interview: Autocomplete and Typeahead Service
Designing an autocomplete (typeahead) service is one of the most common system design interview questions, frequently asked at Google, Meta,
System Design
System Design Interview: Ticketing and Seat Reservation System
Designing a ticketing system like Ticketmaster or a seat reservation system for movies/concerts tests your understanding of concurrency, distributed locking,
System Design
System Design Interview: Machine Learning Platform and MLOps
As machine learning moves from research to production, companies need platforms that manage the full ML lifecycle: data ingestion, feature
System Design
System Design Interview: API Gateway and Service Mesh
API gateways and service meshes are the networking backbone of modern microservices architectures. They handle cross-cutting concerns — authentication, rate
Algorithms
Sliding Window and Two Pointer Interview Patterns
Sliding window and two pointer techniques are among the most frequently tested patterns in coding interviews. They convert O(n²) or