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LeetCode in Java

System Designs

Introduction to System Design for Interviews

System design is a critical skill for software engineers, especially when interviewing for big tech companies. It involves designing scalable, reliable, and efficient systems to meet specific requirements. During system design interviews, you’ll be evaluated on your ability to:

  1. Understand Requirements: Clarify and prioritize functional and non-functional requirements (e.g., scalability, availability, latency).
  2. Design High-Level Architecture: Propose a high-level system architecture, including components, interactions, and data flow.
  3. Deep Dive into Components: Discuss the design of key components (e.g., databases, caching, load balancing, APIs).
  4. Handle Scalability and Performance: Address how the system will scale with increasing load and optimize for performance.
  5. Ensure Reliability and Fault Tolerance: Design for high availability, fault tolerance, and disaster recovery.
  6. Consider Trade-offs: Make informed decisions about trade-offs (e.g., consistency vs. availability, latency vs. throughput).
  7. Communicate Effectively: Clearly explain your thought process and justify your design choices.

Key Topics to Prepare for System Design Interviews

  1. Basic Concepts:

    • Scalability (vertical vs. horizontal)
    • Latency, throughput, and bandwidth
    • Availability and reliability
    • Consistency models (strong, eventual)
    • CAP theorem

  2. System Components:

    • Load balancers
    • Databases (SQL vs. NoSQL, indexing, partitioning, replication)
    • Caching (in-memory caches like Redis, CDNs)
    • Message queues (Kafka, RabbitMQ)
    • Distributed systems (consensus algorithms like Paxos, Raft)

  3. Design Patterns:

    • Microservices vs. monolithic architecture
    • Event-driven architecture
    • Publisher-subscriber model
    • Sharding and partitioning

  4. Real-World Systems:

    • Design a URL shortener (e.g., TinyURL)
    • Design a social media feed (e.g., Twitter, Instagram)
    • Design a chat application (e.g., WhatsApp, Slack)
    • Design a video streaming platform (e.g., Netflix, YouTube)
    • Design a ride-sharing service (e.g., Uber, Lyft)
    • Design a search engine (e.g., Google)

  5. Advanced Topics:

    • Distributed caching
    • Data replication and consistency
    • Rate limiting and throttling
    • Distributed locking
    • Handling large-scale data (MapReduce, BigTable)

Common System Design Interview Questions

Here’s a list of frequently asked system design questions in big tech company interviews:

  1. Basic System Design:

    • Design a URL shortener (e.g., TinyURL).
    • Design a rate limiter.
    • Design a key-value store (e.g., Redis).
    • Design a notification system.

  2. Social Media and Communication:

    • Design a social media feed (e.g., Twitter, Instagram).
    • Design a chat application (e.g., WhatsApp, Slack).
    • Design a newsfeed ranking system (e.g., Facebook).

  3. E-commerce and Marketplaces:

    • Design an e-commerce platform (e.g., Amazon).
    • Design a ride-sharing service (e.g., Uber, Lyft).
    • Design a food delivery app (e.g., DoorDash, Uber Eats).

  4. Streaming and Content Delivery:

    • Design a video streaming platform (e.g., Netflix, YouTube).
    • Design a music streaming service (e.g., Spotify).
    • Design a content delivery network (CDN).

  5. Search and Recommendation Systems:

    • Design a search engine (e.g., Google).
    • Design a recommendation system (e.g., Netflix, Amazon).
    • Design an autocomplete system (e.g., Google Search).

  6. Storage and Databases:

    • Design a distributed file storage system (e.g., Dropbox, Google Drive).
    • Design a distributed database (e.g., Cassandra, DynamoDB).
    • Design a logging system (e.g., Splunk, ELK stack).

  7. Scalability and Performance:

    • Design a system to handle millions of concurrent users.
    • Design a system for real-time analytics.
    • Design a system for handling large-scale data processing (e.g., MapReduce).

  8. Advanced System Design:

    • Design a distributed cache (e.g., Memcached, Redis).
    • Design a distributed locking mechanism.
    • Design a system for leader election in a distributed system.

How to Prepare

  1. Study Fundamentals: Understand the core concepts of system design, including scalability, availability, and consistency.
  2. Practice Designing Systems: Use real-world examples to practice designing systems from scratch.
  3. Mock Interviews: Participate in mock interviews to simulate the interview environment and get feedback.
  4. Review Case Studies: Study how real-world systems are designed (e.g., Netflix, Google, Amazon).
  5. Use Resources: Leverage books, online courses, and blogs to deepen your understanding.
  • Books:
    • “Designing Data-Intensive Applications” by Martin Kleppmann
    • “System Design Interview” by Alex Xu
  • Online Courses:
    • Grokking the System Design Interview (Educative)
    • System Design Primer (GitHub)
  • Websites:

Final Tips

  • Clarify Requirements: Always start by asking clarifying questions to understand the problem fully.
  • Think Aloud: Communicate your thought process clearly and justify your design decisions.
  • Iterate and Improve: Be open to feedback and iterate on your design to make it better.
  • Focus on Trade-offs: Be prepared to discuss the trade-offs in your design (e.g., consistency vs. availability).