Merge pull request #228 from ephemient/hs/day19

hs/src/Day19.hs

@@ -6,26 +6,20 @@
 -- Description:    <https://adventofcode.com/2024/day/19 Day 19: Linen Layout>
 module Day19 (solve) where
 
-import Control.Parallel.Strategies
+import Control.Parallel.Strategies (parMap, rseq)
 import Data.Foldable (foldMap')
 import Data.Monoid (Sum (Sum))
 import Data.Text (Text)
-import Data.Text qualified as T (lines, null, splitOn)
-import Data.Text.Array qualified as A (equal)
-import Data.Text.Internal (Text (Text))
-import Data.Text.Unsafe qualified as T (lengthWord8)
+import Data.Text qualified as T (isSuffixOf, lines, null, splitOn)
+import Data.Text.Unsafe qualified as T (lengthWord8, takeWord8)
 import Data.Vector qualified as V (generate, (!))
 
 count :: [Text] -> Text -> Int
 count keys target = getCount $ T.lengthWord8 target
   where
     counts = V.generate (T.lengthWord8 target) getCount
     getCount 0 = 1
-    getCount i = sum [counts V.! (i - T.lengthWord8 key) | key <- keys, key `isSuffixOfAt` i $ target]
-
-isSuffixOfAt :: Text -> Int -> Text -> Bool
-isSuffixOfAt (Text a aoff alen) n (Text b boff blen) =
-  alen <= n && n <= blen && A.equal a aoff b (boff + n - alen) alen
+    getCount i = sum [counts V.! (i - T.lengthWord8 key) | key <- keys, key `T.isSuffixOf` T.takeWord8 i target]
 
 solve :: Text -> Maybe (Int, Int)
 solve (T.lines -> (T.splitOn ", " -> keys) : rest) | not $ any T.null keys = Just (part1, part2)