I've definitely seen interviewers (both by reading other people's feedback, and in one rare case, being an interviewee) who expected a "correct" answer and wouldn't work with the candidate to get there if they didn't already know it.

See also: overused brainteasers. I remember being asked the 5 litre / 3 litre / get 4 litres problem for my Microsoft intern interview, and honestly told them that I already knew the answer, so I wouldn't be "solving" it, but here it is anyway...