AoC/2020/day10/day10.hs
2020-12-11 00:28:13 +01:00

19 lines
498 B
Haskell

import Control.Monad
import Data.List
main :: IO ()
main = do
input <- map read . lines <$> readFile "input"
print $ (product . map length . group . sort . jolts) input
print $
(product .
map (last . trib [0, 0, 1] . sum) . filter (elem 1) . group . jolts)
input
jolts :: [Integer] -> [Integer]
jolts = ap (zipWith subtract) tail . (\x -> 0 : x ++ [last x + 3]) . sort
trib :: [Integer] -> Integer -> [Integer]
trib x 0 = x
trib [x, y, z] n = trib [y, z, x + y + z] (n - 1)