I am quite disappointed with the all solutions of this kata, since in my opinion the main and only difficulty was precisely in using the string builder correctly instead of string concatenation.

For example, in one of the worst cases, getPINs("55558888") will produce up to 97 thousand extra String objects because of string concatenation."

perfect examples of a simple problem solved with something that is really not worth trying to understand

can someone explain the regex in the the pattern?

I wish I could vote on Best Practices and Clever at the same time :)

Someone can give me feedback about my solution?

Great solution :o

he go through all values untill a square root of num as i inderstand

Not safe.
commentSymbols : {"A", "-", "Z"}

concize, but hard to understand, so it's clever as well as it's not a best practice

My Solution works too :-)

my solution is definitely better than this.

Really short. Is it easy to understand to whoever could get this for maintenance, in production?

Why go over the whole 2d array over and over again to check for 0s, check for redundants, when you can just check everything by going over the array just for one time.