I cleared up some of the mess. Hope it's better now.

Why do you need to use compact here? I tried you algorithm without it for a few cases and it seemed to still work.

It's a bad thing we can't check that coincidence

Nope, that’s absolutely not how it works.

The burden of proof lies entirely with the person who makes the allegations, i. e. you.

So it’s not “a bad thing we can’t check”. The only thing that may be unfortunate here is the fact that you’ve decided to jump to conclusions instead of substantiating your claims.

"So you’re saying the solution is so easy that it constitutes cheating?"

If that's the case it shouldn't have to be in this category

"So you’re saying the solution is so difficult that > 100 people can’t possibly have come up with it independently without using Google?"

It's a bad thing we can't check that coincidence

but the idea of having such problem is to actually code the solution.

So you’re saying the solution is so easy that it constitutes cheating?

Try Googling Rot13 Ruby you'll find exactly the same.

So you’re saying the solution is so difficult that > 100 people can’t possibly have come up with it independently without using Google?

Probably the author is not aware of such method in Ruby, but the author mentioned that using 'encode' in python was considered cheating(for instance). If you would have done that in python it would be as easy as writing string.encode('rot13'). I know Ruby has bunch of methods and the language itself is quite simple to use but the idea of having such problem is to actually code the solution.

The reason I accuse others for using the same solution is just because you can find it in StackOverflow or any other website. Try Googling Rot13 Ruby you'll find exactly the same.

If you think this is cheating, go code in C. This is Ruby, and it's done like this in Ruby.

Also, if the kata author have not actually disabled the relevant built-ins, it's considered not disabled no matter how the kata author says otherwise. As the old saying goes, show, not tell.

This is obviously, cheating. You're not suppossed to use ruby's methods that already solve the problem, you're supposed to code your own solution by thinking, not by copying and pasting what you first find in Google.

The description is not clear enough, it should include at least one more example of how it works.