day3

day2/app/Pt1.hs

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+module Main (main) where
+
+import Text.Printf (printf)
+
+main :: IO ()
+main = do
+  inputs <- readFile "./inputs/day2"
+  let columns = map (map (read :: String -> Int) . words) (lines inputs)
+
+  printf "safe: %d\n" $ length $ filter safe columns
+
+safe :: (Ord a, Num a) => [a] -> Bool
+safe x = distance x && ascOrDesc x
+
+distance :: (Ord a, Num a) => [a] -> Bool
+distance [] = True
+distance [_] = True
+distance (x : y : xs) = abs (x - y) <= 3 && abs (x - y) >= 1 && distance (y : xs)
+
+ascOrDesc :: (Ord a, Num a) => [a] -> Bool
+ascOrDesc [] = False
+ascOrDesc [_] = False
+ascOrDesc (x : y : xs) = (x < y && asc (x : y : xs)) || (x > y && desc (x : y : xs))
+
+asc :: (Ord a, Num a) => [a] -> Bool
+asc [] = True
+asc [_] = True
+asc (x : y : xs) = x < y && asc (y : xs)
+
+desc :: (Ord a, Num a) => [a] -> Bool
+desc [] = True
+desc [_] = True
+desc (x : y : xs) = x > y && desc (y : xs)

day2/app/Pt2.hs

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+module Main (main) where
+
+import Data.List (delete)
+import Text.Printf (printf)
+
+main :: IO ()
+main = do
+  inputs <- readFile "./inputs/day2"
+  let columns = map (map (read :: String -> Int) . words) (lines inputs)
+
+  -- print $ filter safe columns
+  printf "safe w damper: %d\n" $ length $ filter safe columns
+
+safe :: (Ord a, Num a) => [a] -> Bool
+safe x = distance x x x && ascOrDesc x
+
+distance :: (Ord a, Num a) => [a] -> [a] -> [a] -> Bool
+distance full arr (x : y : xs)
+  | length arr < length full - 1 = False
+  | abs (x - y) <= 3 && abs (x - y) >= 1 = distance full arr (y : xs)
+  | otherwise = distance full (delete y arr) (x : xs)
+distance full arr [_] = length arr >= length full - 1
+distance _ _ _ = False
+
+ascOrDesc :: (Ord a, Num a) => [a] -> Bool
+ascOrDesc (x : y : xs)
+  | x < y = asc (x : y : xs) (x : y : xs) (x : y : xs)
+  | x > y = desc (x : y : xs) (x : y : xs) (x : y : xs)
+ascOrDesc _ = False
+
+asc :: (Ord a, Num a) => [a] -> [a] -> [a] -> Bool
+asc full arr (x : y : xs)
+  | length arr < length full - 1 = False
+  | x < y = asc full arr (y : xs)
+  | x >= y = asc full (delete y arr) (x : xs)
+asc full arr [_] = length arr >= length full - 1
+asc _ _ _ = False
+
+desc :: (Ord a, Num a) => [a] -> [a] -> [a] -> Bool
+desc full arr (x : y : xs)
+  | length arr < length full - 1 = False
+  | x > y = desc full arr (y : xs)
+  | x <= y = desc full (delete y arr) (x : xs)
+desc full arr [_] = length arr >= length full - 1
+desc _ _ _ = False

day2/day2.cabal

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+cabal-version: 2.2
+
+-- This file has been generated from package.yaml by hpack version 0.37.0.
+--
+-- see: https://github.com/sol/hpack
+
+name:           day2
+version:        0.1.0.0
+description:    Please see the README on GitHub at <https://github.com/githubuser/day2#readme>
+homepage:       https://github.com/githubuser/day2#readme
+bug-reports:    https://github.com/githubuser/day2/issues
+author:         Author name here
+maintainer:     example@example.com
+copyright:      2024 Author name here
+license:        MIT
+build-type:     Simple
+
+source-repository head
+  type: git
+  location: https://github.com/githubuser/day2
+
+executable day2pt1
+  main-is: Pt1.hs
+  other-modules:
+      Paths_day2
+  autogen-modules:
+      Paths_day2
+  hs-source-dirs:
+      app
+  ghc-options: -Wall -Wcompat -Widentities -Wincomplete-record-updates -Wincomplete-uni-patterns -Wmissing-export-lists -Wmissing-home-modules -Wpartial-fields -Wredundant-constraints -threaded -rtsopts -with-rtsopts=-N
+  build-depends:
+      base >=4.7 && <5
+  default-language: Haskell2010
+
+executable day2pt2
+  main-is: Pt2.hs
+  other-modules:
+      Paths_day2
+  autogen-modules:
+      Paths_day2
+  hs-source-dirs:
+      app
+  ghc-options: -Wall -Wcompat -Widentities -Wincomplete-record-updates -Wincomplete-uni-patterns -Wmissing-export-lists -Wmissing-home-modules -Wpartial-fields -Wredundant-constraints -threaded -rtsopts -with-rtsopts=-N
+  build-depends:
+      base >=4.7 && <5
+  default-language: Haskell2010