The one whiteboarding code review I had was to pseudocode a merge sort on the board. I knew the question he was going to ask because I had two coworkers who had gone through the process previously, one had worked with the company and the other declined the offer.

I already had an offer by then but I did the interview for grins and giggles and didn’t try to remember what a merge sort was. I actually wanted to test the culture of the company. If they ask me to write a merge sort and I don’t know the algorithm, will they describe it on a high level or will they look at me derisively? That would tell me a lot about the company.

Well anyway, the guy was nice enough, I did the mergesort on the board, got an offer but decided if their interview for “senior engineers” consisted of the ability to do a merge sort instead of deeper architectural questions, that wasn’t the company I wanted to work for.

When I conduct interviews, I have a simplified non working (but compiling) class that is a sample of the types of problems we solve everyday with a set of failing unit tests. We pair program and they have to see if the tests pass.