I've been working through them and the difficulty has been all over the map. I've gotten a couple of [what I thought were] moderately hard, whereas one problem

I've been working through them and the difficulty has been all over the map. I've gotten a couple of [what I thought were] moderately hard, whereas one problem basically had a very complicated phrasing, but the answer ended up being [length of the input vector] - 1, plus some other trivial ones. It's pretty fun though, even if you're not looking for an interview.