I thought of using a hash, but how to handle a range wherein the limits are not in the actual set was not obvious to me. I guess I could use the same thing but use exists en lieu of defined. But then again aren't hashes notoriously suboptimal for numbers? (strings of a limited set of characters)

Not interesections, trying to find the existing elements within the defined range.

--
I'm not belgian but I play one on TV.