FWIW, when I attend an interview, as either party, I want to have a discussion, a bit of back-and-forth, and crucially to determine if it's likely we'd be able to get on, day to day. Coding competency is not the only important thing. And anyway, it can easily be established via a bit of white-boarding, conversation, and preparatory reviews of any existing work they have online. If you are in doubt, then maybe pair on a fun little algorithm,... something that's not solved, and not dull. Something original would be best.
Being given a pre-packaged task to complete feels very procedural and bland...