I think usize would be a better choice for the format of the "length" parameter.

I have forked it.

Thanks for taking a look!

Merge conflict.

Thank you :-)

I like the use of mem::swap on gcd() function. Good work!

approved by someone

Oh, cool. And due to it being Cow I assume it saves some calls to .to_owned() for the else branch, as Join takes &str.

I'll look into this some more. Thanks for the fork! :-)

I just saw this today in the source of regex crate, I'm not 100% sure how it works yet, but I assume to_owned shouldn't be called here because there's nothing that needs specifically a String: it's Vec<Cow<_>> and then Join just uses Borrow<str>.

Oh, interesting! Do you mind explaining what exactly the difference is in this case? I thought it would end up calling .to_owned() on the string slice regardless?

https://doc.rust-lang.org/src/alloc/string.rs.html#2234-2240

Thanks for taking a look!

Forked, updated to 1.50 and hopefully fixed.

Merge conflict.

It should be fixed here: https://www.codewars.com/kumite/60637c75fb053700324c175d?sel=60648e7477c71400430cb9df