Low Level Design

Object-oriented design and clean architecture principles.

Framework

• What do you actually do in a LLD Interview?
  • Patterns (deep dives per variation type)
    • Strategy Variation Playbook
      • Problems
        • Parking Lot
        • Movie Ticket Booking
        • Delivery Agent Assignment
        • Ride Sharing
        • Pluggable Eviction Cache
        • Rate Limiter
        • Splitwise
        • Twitter Feed
    • State Variation Playbook
      • Problems
        • Food Delivery
        • Vending Machine
    • Command Variation Playbook
      • Problems
        • Pub-Sub Message Queue
        • Text Editor
    • Rule-Chain Variation Playbook
      • Problems
        • Chess
        • Online Shopping
    • Data-Driven Variation Playbook
      • Problems
        • Snake & Ladder
        • Coffee Machine
        • Stack Overflow
        • Task Planner
    • Structure-Driven Problems Playbook
      • Problems
        • LRU Cache
        • Stock Exchange Matching

Concepts

• Design Patterns, all 26, Creational/Structural/Behavioral, full writeups below.
• SOLID Principles, all five, each with the failure it prevents.
  • Single Responsibility
  • Open/Closed
  • Liskov Substitution
  • Interface Segregation
  • Dependency Inversion

Coming soon…

• UML Diagrams
• Class Design
• Interface Design
• Dependency Injection
• Clean Code Practices
• Code Refactoring

Design Patterns

• Design Patterns
  • Creational Patterns
  • Structural Patterns
  • Behavioral Patterns
• Case study: Designing a Document Editor — one design, five patterns falling out of it

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