I know this is an old comment, so this is for whoever sees this.
Ruby seems like a bit of an outlier, as it's naturally less verbose
than most other languages. At least in my experience, once you become
familiar with all of the most commonly used ruby methods, one liners
like this can actually be just as understandable (if not more so) as
more verbose code.

Added sample tests and updated description.

Also, just like StackOverflow, fastest gun in the west effect applies, and it's mostly everyone upvoting on the same early solution that was top because it was top and hence most visible.

Also, voting system is popularity vote so it's not necessarily a good indicator at all. Do you want to listen to 1000 novices, or 3 very experienced coders explaining the same topic? ;-)

Best Practices or Clever depends upon who you talk to, and whether they had their coffee yet, or which day of the week it is. for example, one might insist that Best Practices applies to this solution, while another might remind us how code golf is not always the best solution. also, Best Practices seems more presumptive than Clever, since Best Practices conforms to some standard, while Clever is basically like saying cool bro

since a vote basically means thumbs up, choose either one

Clean and readable solution

I believe it is to do with the readibility. It's almost English !!!

Sorry if this sounds stupid, but: What's the exploit in your solution? I used a similar solution and thought it was the intended one.

I was mildly confused by the usage of "nd" as well. May I suggest using "stop", "final", "terminal", "limit", "endpoint" or something similar?

At the risk of sounding stupid: What exactly is your reasoning behind that, @Absurdated?

This practice is tipical for polymorphic functions. Usualy polymorphic functions differ argument tuple but this fucntion is polymorphic because has two diffirent definitions for n > 0 and n < 0.

When [[1,2],[3,4],[5,6]] passed, it should return nil, but solution witch returns 4 passes all tests.

Yes, I think you're right. My solution is bad.

Sounds as if your solution might be getting stuck in an infinite loop.