aoc2021/app/D1P2.hs

module Main where

main :: IO ()
main = interact solution

windows :: Int -> [a] -> [[a]]
windows _ [] = []
windows n (a:r) = take n (a:r) : windows n r

solution :: String -> String
solution =
  show
  . sum
  . map (fromEnum . (\(a:b:_) -> a < b) )
  . init
  . windows 2
  . map sum
  . init . init
  . windows 3
  . map (read :: String -> Int)
  . lines