adventofcode1701/app/advent01.hs

   1 {-# LANGUAGE NegativeLiterals #-}
   2
   3 module Main(main) where
   4
   5 import Data.Char (digitToInt)
   6
   7 main :: IO ()
   8 main = do
   9         digits <- readFile "data/advent01.txt"
  10         print $ part1 digits
  11         print $ part2 digits
  12
  13 part1 :: String -> Int
  14 part1 = solve 1
  15
  16 part2 :: String -> Int
  17 part2 digits = solve (length digits `div` 2) digits
  18
  19 -- Verbose version
  20 -- solve n digits = sum $ map (digitToInt . fst)
  21 --                      $ filter (uncurry (==))
  22 --                      $ zip digits
  23 --                      $ drop n
  24 --                      $ cycle digits
  25
  26 solve :: Int -> String -> Int
  27 solve n digits = sum $ zipWith (\a b -> if a == b then digitToInt a else 0) digits
  28                      $ drop n
  29                      $ cycle digits