haskell: 2015 05a

2015/haskell/app/Main.hs

@@ -1,19 +1,24 @@
-{-# LANGUAGE TypeApplications #-}
+{-# LANGUAGE ImportQualifiedPost #-}
+
 module Main where
 
-import qualified Day01
-import qualified Day02
-import qualified Day03
+import Data.Text (Text)
+import Data.Text.IO qualified as TIO
+import Day01 qualified
+import Day02 qualified
+import Day03 qualified
+import Day04 qualified
+import Day05 qualified
 import Text.Printf (printf)
 
-readDay :: Int -> IO String
-readDay n = readFile $ getPath n
+readDay :: Int -> IO Text
+readDay n = TIO.readFile $ getPath n
  where
   getPath n = "../.inputs/" <> printf "%02d" n
 
 main :: IO ()
 main = do
-  content <- readDay 2
-  let parsed = Day02.parse content
-  print $ Day02.solveA parsed
-  print @Int $ Day02.solveB parsed
+  content <- Day05.parse <$> readDay 5
+  print $ Day05.solveA content
+
+-- print @Int $ Day05.solveB parsed

2015/haskell/haskell.cabal

@@ -21,10 +21,7 @@ library
     Day02
     Day03
     Day04
-
-  default-extensions:
-    ImportQualifiedPost
-    OverloadedStrings
+    Day05
 
   -- Modules included in this library but not exported.
   -- other-modules:
@@ -48,6 +45,7 @@ executable haskell
   build-depends:
     aoc2015,
     base >=4.16.4.0,
+    text >=2.1.1,
 
   hs-source-dirs: app
   default-language: Haskell2010

2015/haskell/solutions/Day04.hs

@@ -1,3 +1,6 @@
+{-# LANGUAGE ImportQualifiedPost #-}
+{-# LANGUAGE OverloadedStrings #-}
+
 module Day04 (solveA, solveB) where
 
 import Crypto.Hash.MD5 (hash)
@@ -7,20 +10,20 @@ import Data.ByteString qualified as BS
 import Data.ByteString.Char8 qualified as Char8
 import Text.Printf (printf)
 
-hashHex :: String -> String
-hashHex = concatMap (printf "%02x") . BS.unpack . hash . Char8.pack
+hashHex :: ByteString -> String
+hashHex = concatMap (printf "%02x") . BS.unpack . hash
 
-test :: String
+test :: ByteString
 test = "ckczppom"
 
-solve :: Int -> String -> Integer
+solve :: Int -> ByteString -> Integer
 solve zeros key = fst . head . filter (isMatch . snd) . map toHash $ [1 ..]
  where
-  toHash n = (n, hashHex $ key <> show n)
+  toHash n = (n, hashHex $ key <> Char8.pack (show n))
   isMatch = all (== '0') . take zeros
 
-solveA :: String -> Integer
+solveA :: ByteString -> Integer
 solveA = solve 5
 
-solveB :: String -> Integer
+solveB :: ByteString -> Integer
 solveB = solve 6

2015/haskell/solutions/Day05.hs

@@ -0,0 +1,44 @@
+{-# LANGUAGE ImportQualifiedPost #-}
+{-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE TypeApplications #-}
+
+module Day05 (parse, solveA) where
+
+import Control.Monad (foldM)
+import Control.Monad qualified as T
+import Data.Either (fromLeft)
+import Data.Maybe (fromMaybe, isNothing)
+import Data.Text (Text)
+import Data.Text qualified as T
+
+parse :: Text -> [Text]
+parse = T.lines
+
+isVovel :: Char -> Bool
+isVovel c = elem @[] c "aeiou"
+
+isWrong :: String -> Bool
+isWrong cs = cs `elem` ["ab", "cd", "pq", "xy"]
+
+isNice :: Text -> Bool
+isNice = maybe False (check . snd) . foldM next ('_', (False, 0)) . T.unpack
+ where
+  check :: (Bool, Int) -> Bool
+  check (double, vowels) = double && vowels >= 3
+  next :: ((Char, (Bool, Int)) -> Char -> Maybe (Char, (Bool, Int)))
+  next (prev, (double, vowels)) char =
+    let double' = double || prev == char
+        vowels' = if isVovel char then vowels + 1 else vowels
+     in if isWrong [prev, char]
+          then Nothing
+          else Just (char, (double', vowels'))
+
+solveA :: [Text] -> Int
+solveA = length . filter isNice
+
+test :: Text
+test = "dvszwmarrgswjxmbau"
+
+-- $> isNice test
+
+solveB = undefined