I've had an argument recently with a fellow programmer. He was interviewing for a new position and was asked this question:
Give a sequence of numbers starting at X and ending in Y but with one element missing so N is Y-X-1, find the missing element in O(N) or better.
Now, the answer is irrelevant here (but interesting). This started a discussion on whether this was even a good question to ask during an interview.
One side: Algorithms are an inherit part of programming and a candidates ability to answer this question supports that this candidate will be a good programmer and be able to solve larger problems and can handle most programming tasks which are ultimately easy to understand and answer.
Other side: Writing algorithms from scratch is rarely used in modern programming and therefore is irrelevant in the bigger question of whether the person will be a good programmer. A person could successfully answer this question yet still not be able to do more common programmings tasks.
Your thoughts? Good interview question or not?