[dr_rezzy]

That would only be a risk if we were talking about a typical high school multiple choice test. I would think that a cheater would be filtered out by this point in their career (this point being applying to a high tech company). However, collaborating on a solution is not necessarily a bad thing. I think the goal here is to find candidates which can deliver unique, valuable, and insightful problem solving skills. To go ahead and bottle that process up into a pre determined steps or a 1 hour drill doesnt serve your goals very well. Who knows, maybe these guys have a recipe which works for them. From my own experiences, I would disagree.

[regs]

You'd be surprised at what people will do to game an interview. I've had people give me the correct answer to a question I didn't ask (but from our list of questions) - clearly having gotten from someone else who had interviewed earlier.

Note that algorithms interviews are just one part of a larger inventory that one takes of a candidates, one dimension. Take home and/or whiteboard coding can be a part of that process as well, but each has its downsides.

What we look for, in particular, is methods that have a very low false positive rate. In person algorithm interviews, where the point is not the 'right' answer but hearing about how someone thinks are in that category. You can't really fake it.