Day 2: Red-Nosed Reports
Megathread guidelines
- Keep top level comments as only solutions, if you want to say something other than a solution put it in a new post. (replies to comments can be whatever)
- You can send code in code blocks by using three backticks, the code, and then three backticks or use something such as https://blocks.programming.dev/ if you prefer sending it through a URL
FAQ
- What is this?: Here is a post with a large amount of details: https://programming.dev/post/22323136
- Where do I participate?: https://adventofcode.com/
- Is there a leaderboard for the community?: We have a programming.dev leaderboard with the info on how to join in this post: https://programming.dev/post/6631465
Love to see your haskell solutions!
I am so far very amazed with the compactness of your solutions, your
lessOneis very much mind-Bending. I have never used or seen<$>before, is it a monadic$?Also I can’t seem to find your logic for this safety condition:
The levels are either all increasing or all decreasing, did you figure that it wasn’t necessary?Thanks! The other two posters already answered your questions, I think :)
Haskell makes it really easy to build complex operations out of simple functional building blocks, skipping a lot of boilerplate needed in some other languages. I find the compactness easier to read, but I realize that not everyone would agree.
BTW, I’m a relative Haskell newbie. I’m sure more experienced folks could come up with even more interesting solutions!
<$>is justfmapas an infix operator.>>> fmap (+1) [1,2,3] [2,3,4] >>> (+1) <\$> [1,2,3] [2,3,4]For the last point, it isn’t needed since the differences between elements should be all positive or all negative for the report to be safe. This is tested with the combination of
negateandgradual.I am also enjoying these Haskell solutions. I’m still learning the language, so it’s been cool to compare my solution with these and grow my understanding of Haskell.