Day 24, Part 1

README.md

@@ -6,5 +6,5 @@ I started learning Haskell very recently, and I just learned this year that Adve
 |01 |★ ★  |06 |★ ★  |11 |★ ★  |16 |★    |21 |     |
 |02 |★ ★  |07 |★ ★  |12 |★    |17 |★ ★  |22 |★    |
 |03 |★ ★  |08 |★ ★  |13 |★ ★  |18 |★ ★  |23 |★    |
-|04 |★ ★  |09 |★ ★  |14 |★ ★  |19 |★    |24 |     |
+|04 |★ ★  |09 |★ ★  |14 |★ ★  |19 |★    |24 |★    |
 |05 |★ ★  |10 |★ ★  |15 |★    |20 |     |25 |     |

adventofcode2024.cabal

@@ -59,4 +59,5 @@ executable adventofcode2024
     Day19
     Day22
     Day23
+    Day24
     Graph

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

src/Main.hs

@@ -21,6 +21,7 @@ import Day18 (day18_1, day18_2)
 import Day19 (day19_1)
 import Day22 (day22_1)
 import Day23 (day23_1)
+import Day24 (day24_1)
 import System.Environment (getArgs)
 
 main :: IO ()
@@ -108,6 +109,7 @@ main = do
     "19" : "1" : _ -> day19_1
     "22" : "1" : _ -> day22_1
     "23" : "1" : _ -> day23_1
+    "24" : "1" : _ -> day24_1
     "all" : _ -> do
       day01_1
       day01_2
@@ -145,4 +147,5 @@ main = do
       day19_1
       day22_1
       day23_1
+      day24_1
     _ -> error "Not implemented"