Case Studies — Foundational — low level design interview guide

Top 6 most-asked multi-pattern LLD problems: Parking Lot, Elevator, BookMyShow, Splitwise, Snake & Ladder, Rate Limiter.

6 lessons · about 5 hours · Interview Soon · 6 worked case studies

Case Studies — Foundational is family 7 of 12 in the Thita low level design course. It holds 0 lessons and 6 worked case studies, and it is marked Interview Soon — the material that comes up in a standard interview loop.

Lessons in Case Studies — Foundational

• Design a Parking Lot System — Core lesson, worked case study, about 45 minutes, asked at Amazon, Google, Microsoft, Uber.
• Design an Elevator System — Core lesson, worked case study, about 45 minutes, asked at Amazon, Microsoft, Flipkart.
• Design Movie Ticket Booking (BookMyShow) — Core lesson, worked case study, about 60 minutes, asked at Amazon, Flipkart, Swiggy, PhonePe.
• Design Splitwise / Expense Sharing — Core lesson, worked case study, about 45 minutes, asked at Google, Microsoft, Flipkart, PhonePe.
• Design Snake-and-Ladder — Core lesson, worked case study, about 40 minutes, asked at Amazon, Microsoft, Flipkart.
• Design a Rate Limiter — Core lesson, worked case study, about 45 minutes, asked at Stripe, Uber, Google, Amazon.

Case studies in Case Studies — Foundational

Each one takes a product brief from this family through the whole worked answer — requirements, estimation, API, data model and trade-offs.

The rest of the low level design course

• OOP Foundations & Class Design — OOP pillars, SOLID principles, entity modeling and class extraction. 3 lessons · about 2.5 hours · Interview Soon.
• Strategy & Factory Patterns — #1 and #4 most tested patterns: eliminate if/else chains with Strategy and create objects without specifying exact classes with Factory. 4 lessons · about 2 hours · Interview Soon.
• State Pattern & State Machines — #2 most tested pattern: state transition tables, vending machine case study embedded. 3 lessons · about 2 hours · Interview Soon · 1 worked case study.
• Observer, Decorator & Behavioral — #3 most tested pattern: Observer for event systems, Decorator for middleware chains, Command for undo/redo. 4 lessons · about 2 hours · Interview Soon · 1 worked case study.
• Concurrency Patterns — Race conditions, locks, BlockingQueue, thread pools, and pool sizing. 4 lessons · about 2 hours · Interview Soon.
• Machine Coding & Interview Execution — Three LLD round formats, time budgets, project structure, and pattern recognition. 2 lessons · about 1 hour · Interview Soon.
• Case Studies — Applied — Advanced combos and data structure design: LRU Cache, Notification System, Chess, Food Delivery. 4 lessons · about 3 hours · Interview Soon · 4 worked case studies.
• Advanced Case Studies — Thread-safe designs, distributed patterns, and domain-heavy problems for SDE-2+ interviews. 8 lessons · about 8 hours · Deep Dive · 8 worked case studies.
• Domain-Specific Patterns — Financial systems, progressive design (Coinbase-style), and game engine patterns. 3 lessons · about 3 hours · Deep Dive.
• Machine Coding Mastery — Company-specific machine coding prep and advanced architectural patterns. 2 lessons · about 2 hours · Deep Dive.
• Architecture Teardowns — Deep dives into Spring IoC, Java Collections, and Python data model internals. 3 lessons · about 3 hours · Deep Dive.

Related interview preparation

• Looking for the practice sheet? — Track your progress against every family as a checklist, with company tags and AI interview practice.
• System Design course — The architecture-level companion: APIs, storage, caching, queues and scaling.
• DSA patterns course — The coding round: the algorithmic patterns behind the problems asked alongside design.
• AI mock interviews — Practise explaining a class diagram out loud against an interviewer that asks follow-ups.