67 lines
2 KiB
Haskell
67 lines
2 KiB
Haskell
|
-- requires cabal install --lib megaparsec parser-combinators
|
||
|
|
module Main (main) where
|
||
|
|
|
||
|
|
import Control.Applicative.Permutations
|
||
|
|
import Control.Monad (void, when)
|
||
|
|
import Data.Char qualified as C
|
||
|
|
import Data.List qualified as L
|
||
|
|
import Data.Map qualified as M
|
||
|
|
import Data.Maybe
|
||
|
|
import Data.Set qualified as S
|
||
|
|
import Data.Void (Void)
|
||
|
|
import Text.Megaparsec
|
||
|
|
import Text.Megaparsec.Char
|
||
|
|
|
||
|
|
exampleExpectedOutput = 2286
|
||
|
|
|
||
|
|
data Draw = Draw Int Int Int deriving (Eq, Show)
|
||
|
|
data Game = Game Int [Draw] deriving Show
|
||
|
|
type Input = [Game]
|
||
|
|
|
||
|
|
type Parser = Parsec Void String
|
||
|
|
|
||
|
|
parseColor :: String -> Parser Int
|
||
|
|
parseColor color = read <$> try (some digitChar <* char ' ' <* string color <* optional (string ", "))
|
||
|
|
|
||
|
|
parseDraw :: Parser Draw
|
||
|
|
parseDraw = do
|
||
|
|
(blue, green, red) <- runPermutation $
|
||
|
|
(,,) <$> toPermutationWithDefault 0 (parseColor "blue")
|
||
|
|
<*> toPermutationWithDefault 0 (parseColor "green")
|
||
|
|
<*> toPermutationWithDefault 0 (parseColor "red")
|
||
|
|
void . optional $ string "; "
|
||
|
|
return $ Draw blue green red
|
||
|
|
|
||
|
|
parseGame :: Parser Game
|
||
|
|
parseGame = do
|
||
|
|
id <- read <$> (string "Game " *> some digitChar <* optional (string ": "))
|
||
|
|
Game id <$> someTill parseDraw eol
|
||
|
|
|
||
|
|
parseInput' :: Parser Input
|
||
|
|
parseInput' = some parseGame <* eof
|
||
|
|
|
||
|
|
parseInput :: String -> IO Input
|
||
|
|
parseInput filename = do
|
||
|
|
input <- readFile filename
|
||
|
|
case runParser parseInput' filename input of
|
||
|
|
Left bundle -> error $ errorBundlePretty bundle
|
||
|
|
Right input' -> return input'
|
||
|
|
|
||
|
|
power :: [Int] -> Draw -> [Int]
|
||
|
|
power [b, g, r] (Draw b' g' r') = [max b b', max g g', max r r']
|
||
|
|
|
||
|
|
process :: Int -> Game -> Int
|
||
|
|
process acc (Game id draws) = acc + product (L.foldl' power [0, 0, 0] draws)
|
||
|
|
|
||
|
|
compute :: Input -> Int
|
||
|
|
compute = L.foldl' process 0
|
||
|
|
|
||
|
|
main :: IO ()
|
||
|
|
main = do
|
||
|
|
example <- parseInput "example"
|
||
|
|
let exampleOutput = compute example
|
||
|
|
when (exampleOutput /= exampleExpectedOutput) (error $ "example failed: got " ++ show exampleOutput ++ " instead of " ++ show exampleExpectedOutput)
|
||
|
|
input <- parseInput "input"
|
||
|
|
print $ compute input
|
||
|
|
|