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
Haskell
Had some fun with arrows.
import Control.Arrow import Control.Monad main = getContents >>= print . (part1 &&& part2) . fmap (fmap read . words) . lines part1 = length . filter isSafe part2 = length . filter (any isSafe . removeOne) isSafe = ap (zipWith (-)) tail >>> (all (between 1 3) &&& all (between (-3) (-1))) >>> uncurry (||) where between a b = (a <=) &&& (<= b) >>> uncurry (&&) removeOne [] = [] removeOne (x : xs) = xs : fmap (x :) (removeOne xs)