2023 day 12: star 1

2023/12/Main1.hs

@@ -0,0 +1,22 @@
+import Control.Applicative (liftA2)
+import Data.List (group)
+import Data.List.Split (splitOn)
+
+matchesConsecutive :: [Int] -> String -> Bool
+matchesConsecutive xs = (==) xs . map length . filter ((==) '#' . head) . group
+
+allSprings :: String -> [String]
+allSprings = foldr (liftA2 (:) . getChars) [""]
+  where
+    getChars c = if c == '?' then ['.', '#'] else [c]
+
+solve :: [Int] -> String -> Int
+solve records = length . filter (matchesConsecutive records) . allSprings
+
+parseLine :: String -> ([Int], String)
+parseLine l = (map read . splitOn "," $ y, x)
+  where
+    (x:y:_) = splitOn " " l
+
+main :: IO ()
+main = print . sum . map (uncurry solve . parseLine) . lines =<< readFile "data.txt"