>can you make that work at scale with a data store that you have no information about? How’s it going to get the data to operate on in the first place? Will your data retrieval query cripple a prod database? Read from replica? How far behind can that data be without making your fancy algorithm useless? How will you parallelize that work set? In-request or background job? Multi-threaded or single thread? What about changing state in multi threaded contexts? Database indexes? Schema design? How will you handle failures in your algorithm? How will you handle malformed data? And most importantly, does what you’re doing benefit the user, or just your epeen?

Some of these questions are perfectly valid during LC coding rounds. Others would be more appropriate in a system design round.