I've taken a whiteboard test that asked me to come up with an algorithm that was difficult for me. I got the job even though my solution was horribly inefficient (and I knew it), and the interviewer later told me that the point wasn't to see what algorithm I knew - it was to see if I acted like an ass when I didn't know stuff.
Not sure that's a good test either. When tasked to figure out something as part of a job, by a manager one knows and trusts, who takes feedback of "I don't know how to do this but I will investigate it", a person may act one way, whereas being tasked with someone's PhD thesis by a stranger on an interview may lead to a very different response.
I know I am far less tolerant of bullshit interviews than I once was, and would have far fewer qualms vocalizing what I'm thinking - "I don't know. If I saw this in real life I'd check Google, because it reads exactly like the sort of contrived problem used in interviews and thus is well documented, and likely solved quickly by those who have memorized it. I am not one of those. I'll take a stab at it now if you just want to see how I reason through it, but if coming up with an efficient, correct implementation is part of your criteria we can probably save both of us the trouble" - is that considered acting like an ass?
