Isntead of result[i] = (BigInteger)Math.Pow(2,i);, I wrote result[i] = Math.Pow(2,i); and it threw an error. Why?

How key=catalog.get works? I don't understand the .get.

What is % for? I read this explanation but I can't understand: https://www.php.net/manual/en/function.sprintf.php

% A literal percent character. No argument is required.

Thank you :)

Thank you :)

Thanks :)

Is JS .flat() unavailavle on Codewars?

I don't know why -1 of arr.length - 1 is necessary.

Thank you :)

I know || means OR, but I didn't know |. Now I got it! It's a bitwise OR. Thank you!

@stonith

Thank you!

I posted an explanation of this solution to evarx78's comment. I hope it will help you too.