Next in Line

A medium Python interview practice problem on DataDriven. Write and execute real python code with instant grading.

Domain

Python

Difficulty

medium

Seniority

L4

Problem

A server pool's dispatch layer is driven by a replayed command stream `ops`, where each entry is a list: `['add_server', id]` registers a server, `['remove_server', id]` deregisters one, and `['get_server']` sends the next request to a server and returns its id. Requests go to servers in the order they registered, wrapping from the last back to the first, and when a server is deregistered the rotation carries on over the survivors so that the server that was due next still serves next, with none skipped or served twice in a single pass. Return the ids produced by the `['get_server']` entries in the order those entries appear; `add_server` and `remove_server` add nothing to the output.

Summary

Every server gets its turn. Keep the line honest as the pool changes.

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