advent06.hs

   1 module Main(main) where
   2
   3 import Data.List (transpose, maximum, minimum, sort, group)
   4 import Data.Tuple (swap)
   5
   6 main :: IO ()
   7 main = do
   8     text <- readFile "advent06.txt"
   9     let message = lines text
  10     part1 message
  11     part2 message
  12
  13 part1 :: [String] -> IO ()
  14 part1 message = do
  15     putStrLn $ map (snd . maximum . counts) $ transpose message
  16
  17 part2 :: [String] -> IO ()
  18 part2 message = do
  19     putStrLn $ map (snd . minimum . counts) $ transpose message
  20
  21 counts :: (Eq a, Ord a) => [a] -> [(Int, a)]
  22 counts = map (\g -> (length g, head g)) . group . sort