If that is the only kind of problem your company works on then it is a great question to ask just that problem. I like to ask a wide variety of questions to make sure I don't just target someones strengths or weaknesses.
The sad part is it's still really just a FizzBuzz. I get resumes from lots of people with really great backgrounds who just can't write simple code. I'd love to ask more interesting, varied questions but three out of four candidates don't have the tools to solve those.