day 25

Signed-off-by: Amneesh Singh <natto@weirdnatto.in>

aoc2024.cabal

@@ -184,3 +184,8 @@ executable day24
   build-depends:
     , containers
     , libaoc
+
+executable day25
+  import:         common
+  hs-source-dirs: src
+  main-is:        Day25.hs

src/Day25.hs

@@ -0,0 +1,33 @@
+module Main where
+
+import Data.List (partition)
+
+group :: [[a]] -> [[[a]]]
+group [] = []
+group ([] : xs) = group xs
+group xs = take 7 xs : group (drop 7 xs)
+
+part1 :: [[String]] -> [[String]] -> Int
+part1 locks keys =
+  length
+    [ ()
+      | lock <- locks,
+        key <- keys,
+        and
+          [ l == '.' || k == '.'
+            | (lrow, krow) <- zip lock key,
+              (l, k) <- zip lrow krow
+          ]
+    ]
+
+main :: IO ()
+main =
+  do
+    (locks, keys) <-
+      partition ((== '#') . head . head)
+        . group
+        . lines
+        <$> readFile "./inputs/day25.in"
+
+    putStr "Part 1: " >> print (part1 locks keys)
+    putStrLn "Part 2: See you next year :D"