Question from a noob – would this (at scale, for instance) use more memory by creating two separate iterators, or would the compiler optimise this somehow?

Yeah, i see your point. But could one not argue that if u32 as char could panic depending on the u32 value, why is it any different than knowing the risk of a i32 panicking in the case of a -ve value for example?

Had no idea you could chain casts like that – very nice! (though it seems redundant to not allow i32 as char ?)

As a complete newcomer to Rust, thank you for the comments! If only more people did this on Fundamentals kata instead of code golf!

Love it. Just picking up C++ but very satisfying to see (what I feel is) some exemplary code on an 8kyu!!

Wow, I spent so long on this kata I got logged out and submitted it as a guest by accident.

Of course that exists... damn it python

Thanks for the heads up, adjusted the test cases and that shouldn't work now!