Day 24, Part 1

src/Day24.hs

@@ -0,0 +1,34 @@
+{-# OPTIONS_GHC -Wno-incomplete-uni-patterns #-}
+
+module Day24 (day24_1) where
+
+import Data.Bits
+import qualified Data.HashMap.Strict as M
+import Data.List (sort)
+import Data.List.Split (splitOn)
+
+getWireValue :: String -> M.HashMap String (Maybe Int) -> M.HashMap String String -> Int
+getWireValue w wm cm =
+  case wm M.! w of
+    Just x -> x
+    Nothing ->
+      let (w1 : op : w2 : _) = words $ cm M.! w
+       in if op == "AND"
+            then getWireValue w1 wm cm .&. getWireValue w2 wm cm
+            else
+              if op == "OR"
+                then getWireValue w1 wm cm .|. getWireValue w2 wm cm
+                else getWireValue w1 wm cm `xor` getWireValue w2 wm cm
+
+toDecimal :: [Int] -> Int
+toDecimal n = sum $ zipWith (*) n (iterate (*2) 1)
+
+day24_1 :: IO ()
+day24_1 = do
+  [inputs, connections] <- splitOn [""] . lines <$> readFile "input/day24.txt"
+  let inputsList = [(i, Just ((read :: String -> Int) v)) | [i, v] <- map (splitOn ": ") inputs]
+      wireConnections = [(w, c) | [c, w] <- map (splitOn " -> ") connections]
+      connectionsMap = M.fromList wireConnections
+      wiresMap = M.fromList $ [(fst wc, Nothing) | wc <- wireConnections] ++ inputsList
+      outputs = map (\x -> getWireValue x wiresMap connectionsMap) (filter (\(x : _) -> x == 'z') . sort $ M.keys wiresMap)
+  print $ toDecimal outputs