Fixed.

Rust translation ready for review.

That is entirely up to you. "" is a string like any other, and so parensToTree("") should return some kind of tree, so that if you call treeToParens on that tree, you get the empty string back again.

This is not an issue with the kata, so I am going to close this.

example tests pass when clicking "attempt", but fail when submitting !
for the edge case: parensToTree(""), should the function return undefined, null, empty sring or what ?

so clean 😂😂😂

1- Exception while generating random tests when using Kotlin 1.5: "function toLowerCase() is deprected, use lowercase()"
2- instructions needs improvement

Nice kata, made my brain hurl a little lol

Closing.

I'd like to know how that works. Wouldn't it trigger infinite loop?

don't mutate the input.