you can see his solution... there you will see why

well it's an O(n) solution and there is an obvious O(1) solution

that's why it does not deserve its insane 250 upvotes

explain further since you aren't making any sense.

I'm only doing Rust Katas because I've never used it before. It's nice to say why you think iterators are no good here, otherwise you're sort of trolling.

Indeed, but it is rarely needed to be able to handle real infinity.