Object-Oriented Design
SDE-2Low-level design questions with SOLID principles and design patterns.
Overview
Key concepts
Common OOD questions
Design a parking lot · Design an elevator system · Design a library management system · Design Amazon Locker
Key patterns
Singleton · Factory · Observer · Strategy · Decorator — know when and why to use each.
Question Bank
Practice questions
Common questions asked at Amazon for this topic. Check them off as you practice. Progress is saved in your browser.
Design a parking lot system supporting multiple levels and different spot types.
MediumDesign Amazon Locker — packages are assigned to lockers; customers retrieve with a code.
HardDesign a library management system (checkout, return, search, reservations).
MediumDesign an elevator control system for a multi-floor building.
HardDesign a standard deck of playing cards and implement a Blackjack game.
EasyResources
Go deeper
Free, curated materials to supplement your prep.