day08: interactify

2023/day08/day08.hs

@@ -7,14 +7,12 @@ import qualified Data.Map as M
 
 type LR a = (a, a) -> a
 
-main :: IO ()
-main = do
-  (directions, input) <- parse . lines <$> readFile "input"
-  print $ day08a directions input "AAA"
-  let starts = filter ((== 'A') . last) (M.keys input)
-  print $ day08b directions input starts
+type Tunnels = M.Map String (String, String)
 
-parse :: [String] -> ([LR String], M.Map String (String, String))
+main :: IO ()
+main = interact $ show . day08 . parse . lines
+
+parse :: [String] -> ([LR String], Tunnels)
 parse =
   cycle .
   map
@@ -30,9 +28,14 @@ parseLine s = (a, (b, c))
   where
     [a, b, c] = wordsBy (not . isAlphaNum) s
 
-day08a :: [LR String] -> M.Map String (String, String) -> String -> Int
+day08 :: ([LR String], Tunnels) -> (Int, Int)
+day08 (lrs, m) = day08a lrs m *** day08b lrs m $ ("AAA", starts)
+  where
+    starts = filter ((== 'A') . last) (M.keys m)
+
+day08a :: [LR String] -> Tunnels -> String -> Int
 day08a _ _ [_, _, 'Z'] = 0
 day08a (lr:lrs) m pos = 1 + day08a lrs m (lr (m M.! pos))
 
-day08b :: [LR String] -> M.Map String (String, String) -> [String] -> Int
+day08b :: [LR String] -> Tunnels -> [String] -> Int
 day08b lrs m starts = foldr1 lcm $ map (day08a lrs m) starts

2023/day08/testinput2

@@ -8,3 +8,4 @@ LR
 22C = (22Z, 22Z)
 22Z = (22B, 22B)
 XXX = (XXX, XXX)
+AAA = (ZZZ, ZZZ)