Microsoft Senior Software Engineer Interview Experience — 25 Minutes to Hand-Code a Concurrent Task Executor

I applied pretty randomly online, and HR reached out to schedule an interview for yesterday afternoon. I went in with a "just watching the show" mindset, and honestly the whole experience was terrible — basically a setup for failure. If I'd actually been seriously job hunting, this would have driven me insane.

First, it was a one-hour technical phone screen, and half an hour of that went into going through my resume line by line — nitpicking every single project on it in painstaking detail. I just told myself to stay backward-compatible and patiently answered everything, but at that point I already had a bad feeling.

Then it was time for the coding question: hand-code a multi-currency bounded key executor. 25 minutes, hard limit, and everything had to be implemented.

The requirements were:

A multi-threaded task executor that supports two interfaces:

• boolean submit(String key, Task task) — you need to define Task yourself
• shutdown(int timeout): gracefully shut down all tasks within the timeout

Then a long list of requirements on top of that:

• Tasks under the same key must execute in order
• Tasks across different keys can run in parallel, but at most four tasks can run at the same time
• The total number of scheduled and in-flight tasks cannot exceed 1000
• If shutdown has been initiated, or the total number of scheduled and in-flight tasks does not exceed 1000, submit should return false, otherwise return true
• On shutdown, tasks already executing need to be allowed to finish (or until the timeout hits), while all scheduled tasks get canceled

If you had an AI agent write this, just writing the prompt alone would take 20 minutes. I asked the interviewer whether anyone could actually pull this off in 20 minutes, and they wouldn't give a straight answer. This person is honestly a plague on humanity. I hope the world has a little less malice in it.