In a programming interview if I am asked a question I already know the answer for, such as giving an algorithm for a particular problem. Should I disclose that to the interviewer? This issue only makes sense when there's a novelty aspect to the question.
One example is "How would you reverse each word in a string, but not their order?". There also seems to be a division between easier stuff, that you are "supposed" to know, such as my example and harder more contrived problems.
Whats your policy and rationale for dealing with this issue? If you are already familiar with the question/brainteaser, should you disclose this in addition to answering the question? Is there any ethical dilemma involved with not disclosing your prior knowledge of the question?