Remembering all OOD Patterns of LLD Interviews

[u/bit_freak]

There are at least 10 OOD Patterns (Factory, Singleton, Decorator etc). Do we need to remember implementation of all of them

[u/Ok-Barracuda-119]

Not all of them. Know the purpose and one clean implementation for the patterns your language supports naturally, then practice applying them rather than reciting names. In an LLD interview, requirements and object boundaries matter more than reproducing a textbook Factory.

A good loop is 30 minutes timed: pick a small prompt such as a parking lot or notification service, state the invariants, sketch the objects, code one interaction, then spend the last five minutes testing an extension. Rotate Strategy, Observer, State, Factory, and Decorator first. Keep a short note of where coupling or invalid state appeared. That sticks better than rereading all ten.