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Comment by shasta | Hacker News Reader

> But do you really learn anything by asking the candidate if they can recite the time complexity of a moving window average algorithm (as I was asked to do by an interviewer yesterday)?

This is actually a trivially easy question that gets to the heart of whether you understand the point of moving averages or not (that you can update a sum by subtracting out the value leaving the window and adding in the value entering the window).

"Programming ability" isn't one dimensional. Whether or not the above question is useful depend entirely on what skills are important in a candidate.

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It's not so much specifically about the moving average problem. I would want to see that a candidate can reason about the performance of some code / algorithm. I would not expect them to be able to recite the performance for specific algorithms from memory, however.

I agree, but I suspect "recite" was editorializing by the parent.

It wasn't. I was literally asked, "What is the time complexity of the moving window average algorithm over an array?" and when I asked for clarification, I could hear an edge of... I guess frustration in my interviewer's voice.

Granted, by this time, we'd been through a couple of other problems, and time was running short, but I still think it was pretty unprofessional of the interviewer to let frustration or any other sort of negative emotion show during the interview. That, more than anything else, contributed to my own frustration and perception of unfairness in the entire interview process.

Right, but "recite" was editorializing. That implies that the interviewer expected you to produce the answer from memory, as opposed to thinking about it. It's an easy question if you're familiar with moving window averages and know what the interviewer intends. If it was asked apropos of nothing, a request for context seems reasonable, though. It sounds like you probably had a bad interviewer. There seems to be no shortage of software interviewers lacking in "people skills."

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