[millstone]

I'm sorry to hear your interview didn't go well. I know it's a crushing blow to have weeks of build-up undone by a temporary brain fart.

Here is how employers rationalize this: resumes are not reliable. Resumes can include exaggerations, or even outright lies. When looking at your work experience, however great, it's hard for the prospective employer to know if you made any real contribution, or if you were just nominally attached to the project. Your past employers certainly won't say.

So they need to put you on the spot, to make sure you're the real deal. It would admittedly be nice if the questions were targeted towards your experience, but frankly, reversing a linked list is not an unreasonable problem. You should be able to do it.

If you performed well in the other interviews, the linked list may not have sunk you. Finding good engineers is hard, and if you demonstrated mastery exceeding basic CS problems, they may be able to explain away your mistakes as nervousness, tiredness, or just getting befuddled.

[helpless]

You can reference check or see code in github. If nothing is reliable then just invite candidate and play Russian roulette :)