If you want to import a day's worth of access logs into a hash map, you need to take into account not only the time but also the space complexity of this sort of solution.

Depending on how much traffic a service handles and also on the misguided arbitrary beliefs of a reviewer, importing a day's worth of accesses into a hash map can be a gross mistake and deemed a no-hire with prejudice.

This exercise is even dumber if we take into account that something like importing access logs into something like sqlite, querying data, and discarding the database is something that might be as efficient (if not more) and can take a hand-full of lines of code to implement.

Also, personally I'd consider a sign of incompetence complaining about using a proper database to ingest and query data efficiently but also believes that the time complexity of a task which is expected to run once per day is a hire/no-hire deal-maker. Computational complexity matters for code running in a hot path. Beyond that, either you're playing trivial pursuit or failing to understand the basics of what you're doing.