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-- requires cabal install --lib megaparsec parser-combinators heap vector
module Main (main) where
import Control.Applicative.Permutations
import Control.Monad (void, when)
import qualified Data.Char as C
import Data.Either
import Data.Functor
import qualified Data.Heap as H
import qualified Data.List as L
import qualified Data.Map as M
import Data.Maybe
import qualified Data.Set as S
import qualified Data.Vector as V
import qualified Data.Vector.Unboxed as VU
import Data.Void (Void)
import Text.Megaparsec
import Text.Megaparsec.Char
import Debug.Trace
data Pulse = Low | High deriving (Eq, Show)
data Module = Normal | FlipFlop Bool | Conjunction (M.Map String Pulse) | Broadcaster deriving (Eq, Show)
data Configuration = Configuration Module String [String] deriving (Eq, Show)
type Conf = (Module, [String])
type Input = M.Map String Conf
type Parser = Parsec Void String
parseModule :: Parser Module
parseModule = char '%' $> FlipFlop False
<|> char '&' $> Conjunction M.empty
<|> lookAhead (string "broadcaster") $> Broadcaster
<|> lookAhead letterChar $> Normal
parseLabel :: Parser String
parseLabel = some letterChar
parseConfiguration :: Parser Configuration
parseConfiguration = Configuration <$> parseModule
<*> parseLabel <* string " -> "
<*> some (parseLabel <* optional (string ", "))
parseInput' :: Parser Input
parseInput' = M.fromList . map (\(Configuration m s l) -> (s, (m, l))) <$> some (parseConfiguration <* eol) <* 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'
compute :: Input -> Int
compute input = L.foldl' lcm 1 $ computeX 0 (take (length targets) $ repeat Nothing) $ initConjuctions input
where
computeX :: Int -> [Maybe Int] -> Input -> [Int]
computeX i acc input | all isJust acc = fromJust <$> acc
| otherwise = let (acc', input') = compute' [("button", Low, "broadcaster")] i acc input
in computeX (i+1) acc' input'
compute' :: [(String, Pulse, String)] -> Int -> [Maybe Int] -> Input -> ([Maybe Int], Input)
compute' signals i acc input | length stepAll == 0 = (acc, input)
| otherwise = let acc' = map (accStep i stepAll) $ L.zip targets acc
in compute' stepAll i acc' alterAll
where
alterAll :: Input
alterAll = L.foldl' alterOne input signals
alterOne :: Input -> (String, Pulse, String) -> Input
alterOne acc (prev, p, me) = alter p prev me acc (M.lookup me input)
alter :: Pulse -> String -> String -> Input -> Maybe Conf -> Input
alter _ _ _ input (Just (Normal, _)) = input
alter High _ _ input (Just (FlipFlop _, _)) = input
alter Low _ me input (Just (FlipFlop False, l)) = M.insert me (FlipFlop True, l) input
alter Low _ me input (Just (FlipFlop True, l)) = M.insert me (FlipFlop False, l) input
alter p prev me input (Just (Conjunction m, l)) = M.insert me (Conjunction $ M.insert prev p m, l) input
alter p _ _ input (Just (Broadcaster, l)) = input
alter _ _ _ input Nothing = input
stepAll :: [(String, Pulse, String)]
stepAll = L.foldl' stepOne [] signals
stepOne :: [(String, Pulse, String)] -> (String, Pulse, String) -> [(String, Pulse, String)]
stepOne acc (prev, p, s) = step p prev s acc (M.lookup s input)
step :: Pulse -> String -> String -> [(String, Pulse, String)] -> Maybe Conf -> [(String, Pulse, String)]
step _ _ _ acc (Just (Normal, _)) = acc
step High _ _ acc (Just (FlipFlop _, _)) = acc
step Low _ me acc (Just (FlipFlop False, l)) = acc ++ map (set me High) l
step Low _ me acc (Just (FlipFlop True, l)) = acc ++ map (set me Low) l
step p prev me acc (Just (Conjunction m, l)) = let p2 = if length (M.filter (\x -> x == High) $ M.insert prev p m) == length m then Low else High
in acc ++ map (set me p2) l
step p _ me acc (Just (Broadcaster, l)) = acc ++ map (set me p) l
step _ _ _ acc Nothing = acc
initConjuctions :: Input -> Input
initConjuctions input = let r = M.foldrWithKey initConf input input in r
initConf :: String -> Conf -> Input -> Input
initConf c (_, l) input = L.foldl' initOne input l
where
initOne :: Input -> String -> Input
initOne input s = case M.lookup s input of
Just (Conjunction m, l) -> M.insert s (Conjunction (M.insert c Low m), l) input
_ -> input
set :: String -> Pulse -> String -> (String, Pulse, String)
set me p s = (me, p, s)
targets = pointsTo toRx
[toRx] = pointsTo "rx"
pointsTo :: String -> [String]
pointsTo name = L.foldl' (\acc (k, (_, l)) -> if isJust (L.elemIndex name l) then k:acc else acc) [] $ M.assocs input
accStep :: Int -> [(String, Pulse, String)] -> (String, Maybe Int) -> Maybe Int
accStep _ _ (_, Just x) = Just x
accStep i stepAll (t, Nothing) | triggered = Just (i + 1)
| otherwise = Nothing
where
triggered = L.foldl' (trigg t) False stepAll
trigg _ True _ = True
trigg t False (_, Low, u) = t == u
trigg _ _ _ = False
main :: IO ()
main = do
input <- parseInput "input"
print $ compute input
|
