For the last point, it isn't needed since the differences between elements should be all positive or all negative for the report to be safe. This is tested with the combination of negate and gradual.

I am also enjoying these Haskell solutions. I'm still learning the language, so it's been cool to compare my solution with these and grow my understanding of Haskell.

I haven't had to use any exam software recently, but in the past when I did I remember reading that it can detect when the host is virtual and will not run in a VM. Fortunately at the time I still had a windows laptop lying around, but I'd have a real problem if one of a courses now tried to do this.