Skip to main content

Explore Problems

Certifications Quiz Pricing

⌘K

Design Problems - Low Level Design

Course Contents

Getting Ready: Parking Lot System

Requirements for the Parking Lot

Use Case Diagram

Activity Diagram

Code Implementation

Design Patterns Applied

Testing & Edge Cases

Summary & Key Takeaways

Getting Ready: Tic Tac Toe

Requirements for Tic Tac Toe

Code Implementation

Extending to NxN Board

Design Patterns Applied

Testing & Edge Cases

Summary & Key Takeaways

Getting Ready: Snake and Ladder

Requirements for Snake and Ladder

Activity Diagram

Code Implementation

Design Patterns Applied

Testing & Edge Cases

Summary & Key Takeaways

Getting Ready: LRU Cache

Requirements for the LRU Cache

Code Implementation — HashMap + Doubly Linked List

Thread-Safe LRU Cache

Design Patterns Applied

Testing & Edge Cases

Summary & Key Takeaways

Getting Ready: Logging Framework

Requirements for the Logging Framework

Code Implementation

Adding New Log Sinks (Extensibility)

Design Patterns Applied

Testing & Edge Cases

Summary & Key Takeaways

Getting Ready: Vending Machine

Requirements for the Vending Machine

State Machine Diagram

Code Implementation

Design Patterns Applied

Testing & Edge Cases

Extension: Multiple Payment Methods

Summary & Key Takeaways

Getting Ready: Task Management System

Requirements for the Task Manager

Code Implementation

Undo/Redo with Command Pattern

Design Patterns Applied

Testing & Edge Cases

Summary & Key Takeaways

Getting Ready: Elevator System

Requirements for the Elevator System

Use Case Diagram

State Machine Diagram

Scheduling Algorithms (FCFS, SCAN, LOOK)

Code Implementation

Design Patterns Applied

Testing & Edge Cases

Summary & Key Takeaways

Getting Ready: Library Management System

Requirements for the Library System

Use Case Diagram

Sequence Diagram — Book Checkout Flow

Code Implementation

Design Patterns Applied

Testing & Edge Cases

Summary & Key Takeaways

Getting Ready: Meeting Scheduler

Requirements for the Meeting Scheduler

Use Case Diagram

Sequence Diagram — Schedule a Meeting

Code Implementation

Design Patterns Applied

Testing & Edge Cases

Summary & Key Takeaways

Getting Ready: ATM System

Requirements for the ATM

State Machine Diagram

Sequence Diagram — Withdraw Cash

Code Implementation

Design Patterns Applied

Testing & Edge Cases

Summary & Key Takeaways

Getting Ready: Car Rental System

Requirements for the Car Rental System

Use Case Diagram

Code Implementation

Design Patterns Applied

Testing & Edge Cases

Extension: Insurance & Add-Ons

Summary & Key Takeaways

Getting Ready: Pub-Sub System

Requirements for the Pub-Sub System

Sequence Diagram — Publish & Subscribe Flow

Code Implementation

Thread-Safe Message Delivery

Design Patterns Applied

Testing & Edge Cases

Summary & Key Takeaways

Getting Ready: Hotel Management System

Requirements for the Hotel System

Use Case Diagram

State Machine Diagram — Room Status

Code Implementation

Design Patterns Applied

Testing & Edge Cases

Summary & Key Takeaways

Getting Ready: Splitwise

Requirements for Splitwise

Sequence Diagram — Split an Expense

Code Implementation

Debt Simplification Algorithm

Design Patterns Applied

Testing & Edge Cases

Summary & Key Takeaways

Getting Ready: Digital Wallet

Requirements for the Digital Wallet

Sequence Diagram — Transfer Money

Code Implementation

Transaction Safety & Consistency

Design Patterns Applied

Testing & Edge Cases

Summary & Key Takeaways

Getting Ready: Traffic Signal System

Requirements for the Traffic Signal

State Machine Diagram

Code Implementation

Design Patterns Applied

Testing & Edge Cases

Summary & Key Takeaways

Getting Ready: Stack Overflow

Requirements for Stack Overflow

Use Case Diagram

Code Implementation

Reputation & Voting System

Design Patterns Applied

Testing & Edge Cases

Summary & Key Takeaways

Getting Ready: Movie Ticket Booking

Requirements for the Booking System

Use Case Diagram

Sequence Diagram — Book a Ticket

State Machine Diagram — Booking Status

Code Implementation

Concurrent Seat Locking

Design Patterns Applied

Summary & Key Takeaways

Getting Ready: Online Shopping

Requirements for the Shopping System

Use Case Diagram

State Machine Diagram — Order Lifecycle

Sequence Diagram — Place an Order

Code Implementation

Design Patterns Applied

Payment Strategy & Extensibility

Summary & Key Takeaways

Getting Ready: Chess Game

Requirements for the Chess Game

Class Diagram — Piece Hierarchy

Class Diagram — Board & Game

Sequence Diagram — Make a Move

Code Implementation — Board & Pieces

Code Implementation — Game Logic & Rules

Check, Checkmate & Stalemate Detection

Design Patterns Applied

Summary & Key Takeaways

Getting Ready: Ride-Sharing Service

Requirements for the Ride-Sharing System

Use Case Diagram

State Machine Diagram — Ride Lifecycle

Sequence Diagram — Request a Ride

Code Implementation

Matching & Surge Pricing Algorithms

Design Patterns Applied

Summary & Key Takeaways

Getting Ready: Music Streaming

Requirements for the Streaming Service

Sequence Diagram — Play a Song

Code Implementation

Playlist & Queue Management

Subscription Tiers with Decorator

Design Patterns Applied

Summary & Key Takeaways

Getting Ready: Social Network

Requirements for the Social Network

Use Case Diagram

Sequence Diagram — Create a Post

Code Implementation — Users & Friendships

Code Implementation — Posts & Feed

News Feed Generation Algorithm

Design Patterns Applied

Summary & Key Takeaways

Getting Ready: Food Delivery Service

Requirements for the Food Delivery System

Use Case Diagram

State Machine Diagram — Order Lifecycle

Sequence Diagram — Place an Order

Code Implementation

Delivery Assignment Strategy

Design Patterns Applied

Summary & Key Takeaways

Getting Ready: Stock Brokerage

Requirements for the Stock Brokerage

Use Case Diagram

Sequence Diagram — Place an Order

Code Implementation — Order Book

Code Implementation — Matching Engine

Price Alerts with Observer

Design Patterns Applied

Summary & Key Takeaways

Getting Ready: Online Auction

Requirements for the Auction System

State Machine Diagram — Auction Lifecycle

Sequence Diagram — Place a Bid

Code Implementation

Auction Types (English, Dutch, Sealed-Bid)

Design Patterns Applied

Summary & Key Takeaways

Getting Ready: Airline Management

Requirements for the Airline System

Use Case Diagram

Sequence Diagram — Book a Flight

Code Implementation

Multi-Class Pricing Strategy

Design Patterns Applied

Summary & Key Takeaways

Getting Ready: Restaurant Management

Requirements for the Restaurant System

State Machine Diagram — Table & Order Status

Sequence Diagram — Place an Order

Code Implementation

Kitchen Display with Observer

Design Patterns Applied

Summary & Key Takeaways

Getting Ready: Course Registration

Requirements for the Course Registration System

Sequence Diagram — Register for a Course

Code Implementation

Prerequisite Validation (DAG)

Waitlist with Observer

Design Patterns Applied

Summary & Key Takeaways

Getting Ready: Notification System

Requirements for the Notification System

Use Case Diagram

Sequence Diagram — Send Notification Flow

Code Implementation — Multi-Channel (Email, SMS, Push)

Priority Queue & Rate Limiting

Design Patterns Applied

Testing & Edge Cases

Summary & Key Takeaways

Getting Ready: File Storage System

Requirements for the File Storage System

Use Case Diagram

Sequence Diagram — Upload & Download Flow

Code Implementation — Files, Folders, Permissions

Chunked Uploads & Deduplication

Design Patterns Applied

Testing & Edge Cases

Summary & Key Takeaways

Getting Ready: Blocking Queue

Requirements & Concurrency Challenges

Code Implementation — Python

Code Implementation — Java

Testing Concurrent Behavior

Summary & Key Takeaways

Getting Ready: Thread Pool

Requirements & Design Decisions

Code Implementation — Python

Code Implementation — Java

Graceful Shutdown & Edge Cases

Summary & Key Takeaways

Getting Ready: Rate Limiter

Requirements for the Rate Limiter

Token Bucket Algorithm

Sliding Window Algorithm

Leaky Bucket Algorithm

Code Implementation

Summary & Key Takeaways

Getting Ready: Concurrent HashMap

Requirements & Concurrency Challenges

Code Implementation — Segment Locking

Code Implementation — CAS Operations

Performance Benchmarking

Summary & Key Takeaways

Top 10 Tips for LLD Interviews

Common Mistakes and How to Avoid Them

Practice Plan — 30, 60, 90 Day Roadmaps

Course Conclusion & Next Steps

Design Patterns Applied

Examine which design patterns the Tic Tac Toe game uses, why each was chosen over alternatives, and how they keep the design extensible, testable, and SOLID-compliant.

Loading...

Loading content...