Always enjoy doing these but there was one last year that nearly broke me. I think it was day15. It was the worst combination of mind-numbing coding and horribly hard to debug special cases. It was purely convoluted with very little to think about which makes for the worst kind of puzzles
I can totally relate about that particular one, I remember that it destroyed a good part of a weekend for me, and I wrote that about it on Twitter, back in January of this year:
"I have thought about the particular challenges of this year's Advent of Code (which I greatly enjoyed once again, with some intermittent mixed feelings), and my conclusion is that some problems might very well be of similar difficulty levels, but with nevertheless very dissimilar frustration-inducing levels. And I think the frustration level is strongly correlated with the feedback signal one can use to debug. Case in point: Day 15, which was almost impossible to debug, once you had a working solution, versus Day 17, which was actually fun to debug, since the visual signal you could use was so strong."
I strongly disliked the puzzles that quickly devolved to correctly handling a ton of corner cases. 15 and 17 were both in this category.
What's the fun in that? This is like the boring part of being a developer. Without the payment that goes with being a developer.
That one wiped me out for a week too, and caused borderline psychological problems.
Ultimately though I realised that if I followed the description word by word, and made no assumptions, then I got the right solution. Still, a nightmare: you could pass all the examples, or even some alternate real sample data, and still get it wrong if you got the ordering slightly incorrect.
Yeah, it's really frustrating when the text summary is vague and underspecified. It makes it hard to understand exactly the result the author is looking for, which isn't the fun kind of puzzle.
I hit day 15 and stopped last year. There always seems to be one puzzle which is so irritating it no longer seems worthwhile when I could be playing some music or building something in Minecraft or just lazing around on the sofa with the cat.
Day 15 was terrible for me too. The edge condition I missed was that you could both move and attack in a single turn. It only changed the outcome for me in part 2. I was only able to finally debug it by comparing debug outputs every step with a known-good solution.
