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 that just needs curlies
Hint if you want it
@Absinthe I already solved it that way, just wanted to do it using regexes too.