I tried to solve this in Rust. It's not that hard, but it pigeonholes you so hard into a bad design that exposes internals and has a bad memory layout, all of which I was trying to avoid. After a lot of trying to work around the bad design, I passed the local tests, but I was unable to pass the real tests due to the repeated use of design implementation internals that should not have been relied on. Even beyond that, pretty much everything you're being told is a requirement is non-idiomatic Rust: to_vec instead of implementing the From/Into trait, custom map and filter instead of implementing the IntoIter and Iterable traits, custom from_iter instead of implementing the FromIterator trait.

If all of that ever gets fixed, I'd love to try this again. Peace ✌🏻

Agreed! Like most code where you try to make it short beyond reasonable, but that was the challenge here.

well, lets obfuscate it more

I can't wait for the std::iter::Iterator#array_chunks<const N: usize> feature to be stable! Then you won't even need itertools to do this.

😭 why would you poorly obfuscate a function that reverses strings

This is an abomination...

I think that's only a concern if you are writing code for a real-time application and are at the same time very resource-restrained. Otherwise, this shouldn't matter when running code on modern computers.

This isn't even good. You're recreating a huge array every time this is called. And the other option isn't very good either because you'd have a giant array just taking up memory.