@MMMAAANNN's comment was VERY helpful!

but why is part #1 available in 100 languages, and part 2 / 3 / 4 available in Python only? :-(

I cannot check my solution in C# for this part #2.

What does the n != do

Thanks for the suggestion. The current rank will stay.

all languages edited

5q so high for this kata, i think 6q should be correct

we need better random test generators (EDIT: javascript fixed and random tests updated)

Great kata of the series, an all time classic.

done

Description should be language-agnostic

Well done!)
Suggestion to add REGULAR EXPRESSION tag to Kata.

this should really be part of the description

I"d suggest adding 4444 -> MMMMCDXLIV and 1999 -> MCMXCIX for testing all the prefix numbers. My original algorithm had a flaw which meant that these sometimes didn't work but it neverthless managed to pass an attempt because the random cases didn't happen to generate any of these that time.

Java translation

omg