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-rw-r--r--2023/20-Pulse_Propagation/first.hs1
-rw-r--r--2023/20-Pulse_Propagation/second.hs119
2 files changed, 119 insertions, 1 deletions
diff --git a/2023/20-Pulse_Propagation/first.hs b/2023/20-Pulse_Propagation/first.hs
index c43e332..8704be9 100644
--- a/2023/20-Pulse_Propagation/first.hs
+++ b/2023/20-Pulse_Propagation/first.hs
@@ -61,7 +61,6 @@ compute input = let (x, y) = computeX 1000 (0, 0) $ initConjuctions input in x *
computeX i n input = let (n', input') = compute' (1, 0) [("button", Low, "broadcaster")] input
in computeX (i-1) (scoreAdd n n') input'
compute' :: (Int, Int) -> [(String, Pulse, String)] -> Input -> ((Int, Int), Input)
- compute' n [] input = (n, input)
compute' n signals input | length stepAll == 0 = (n, input)
| otherwise = compute' (scoreAdd n $ score stepAll) stepAll alterAll
where
diff --git a/2023/20-Pulse_Propagation/second.hs b/2023/20-Pulse_Propagation/second.hs
new file mode 100644
index 0000000..5eaf39e
--- /dev/null
+++ b/2023/20-Pulse_Propagation/second.hs
@@ -0,0 +1,119 @@
+-- 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