I just realized this

Yes, you're right! Will take it into account in the future :)

You're quite right. I used string too, before passing all tests. The reason, in my opinion, is that string catenation involves repetitive memory allocation 'coz a new string is created each time. But for byte slice, RAM is much more efficient, therefore faster.

Where is the magic? I did almost the same, just was working with strings, not []byte and could not pass the huge tests.

Think twice before cut once.

That's true, REALLY.

Agree~

I admit, I learnt a lot from this kata~

I can only think that: it's designed this way, on purpose~

Yeah, agree~

Same situation here. Hope author will fix it soon.