Tried solving today's #adventofcode using only regex, and it turns out that it's not easy to match a string containing any character consecutively repeated exactly 2 times (but no more).
For example, I want to match "abccd", but not "abcccd".
Hint if you want it
@ihabunek remember that they are sorted, so all duplicates are next to each other. Perhaps if you just count the numbers and look for any with a count of 2
Hint if you want it
@Absinthe I already solved it that way, just wanted to do it using regexes too.
