Heap and Priority Queue Interview Patterns
When to Use a Heap A heap (priority queue) is the right data structure when you need: the minimum or […]
Algorithms
Algorithms
Dynamic Programming Patterns: Tree DP, Digit DP, and Bitmask DP
Beyond Basic DP Once you’ve mastered 1D/2D tabulation and memoization (Fibonacci, LCS, Knapsack, Coin Change), advanced interview problems require recognizing
System Design
System Design Interview: WebRTC and Real-Time Video Architecture
WebRTC Architecture Overview WebRTC (Web Real-Time Communication) is an open standard that enables peer-to-peer audio and video in browsers and
System Design
System Design Interview: Social Graph and Friend Recommendations
Social Graph Requirements A social graph stores relationships between users (friendships, follows, connections) and enables graph queries: friends of friends,
System Design
System Design Interview: Financial Exchange and Matching Engine
Exchange Architecture Overview A financial exchange matches buy and sell orders — a buyer willing to pay $100 for AAPL
System Design
System Design Interview: Job Scheduler and Task Queue
Why Task Queues? Task queues decouple work production from work execution. Instead of processing a long-running task synchronously (blocking the
System Design
System Design Interview: Notification System at Scale
Notification System Requirements A notification system routes messages from producers (application events) to consumers (users) via multiple channels: push notifications
System Design
System Design Interview: Database Indexing and Query Optimization
Why Indexing Matters Without an index, a SELECT with a WHERE clause requires a sequential scan — reading every row
System Design
System Design Interview: Real-Time Collaborative Editing (Google Docs)
The Collaboration Problem Real-time collaborative editing lets multiple users edit the same document simultaneously with all changes visible to all
System Design
System Design Interview: API Rate Limiting and Throttling
Why Rate Limiting? Rate limiting protects services from overload, abuse, and cost explosions. Without it: a single misbehaving client can
Algorithms
Scala Interview Questions: Functional Programming, Case Classes, and Akka (2025)
Scala Interview Overview Scala is the language of Apache Spark, Kafka (originally), Akka, and many financial systems. Interviews at data
System Design
System Design Interview: Secret Management and PKI (Vault, AWS Secrets Manager)
Why Secret Management Matters Secrets (database passwords, API keys, TLS certificates, SSH keys) are the crown jewels of any system.
System Design
System Design Interview: Log Aggregation and Observability Pipeline
Why Log Aggregation? With hundreds of microservices each running multiple replicas, logs are scattered across thousands of containers. Without centralized
Algorithms
Hash Table and HashMap Interview Deep Dive
Why Hash Tables? Hash tables provide O(1) average-case lookup, insertion, and deletion — making them the most versatile data structure
System Design
System Design Interview: Global Content Delivery and Edge Computing
Beyond Basic CDN: Edge Computing A CDN (Content Delivery Network) has historically served static assets — images, CSS, JS —