This is my least favorite type of puzzle in AoC:
- Not really much challenging
- Most of the effort is in understanding the requirement (without possibility to ask for clarifications)
In my case, I spent quite a lot of time trying to understand what the problem statement was; and then, I was going very cautiously to get the things right, since I was not sure about the problem and the strategy to use.
Worth mentioning, it was maybe one of the first times I have seen a string output in AoC. I had to rework the general runner because of this :)