[georgemcbay]

Why retire the question just because you saw it on Glassdoor? The same question was posted to sureinterview last year, so anyone you hired since November is suspect! (If you believe that potential advance knowledge of the question is relevant).

Worse yet, even if you did come up with this problem on your own, this exact problem was a fairly common interview question back in the mid 90s, when string processing interview questions were all the rage for C/C++ programming jobs -- I must have seen it a dozen times in various interviews over the years. The problem is familiar enough that I'd bet a decent amount of money that it must be listed in one of those interview problem books that were popular before the websites for this stuff started showing up over the past couple years... If you really relied on the interviewee having no possible advance knowledge of this question prior to the interview you surely had a false sense of security prior to seeing it appear on glassdoor.

As long as you engage the interviewee to see that s/he really understands the answers they are giving, I don't really see why it matters if the question has appeared on one of these sites. If the interviewee is preparing for their interviews enough that they are actually looking at these sites and understanding the answers to the point where they can intelligently discuss them, that probably already puts them in the upper tier of people you'd want to seriously consider hiring, so retiring the question is probably counter-productive unless you have a non-disclosed alternative that you're sure is as good of a question.