Solve 2023-05

src/AoC.hs

@@ -1,6 +1,7 @@
 module AoC (
   defaultMain,
   runAoC,
+  runAoCExample,
   module AoC.Day,
   module AoC.Year,
 ) where
@@ -20,6 +21,11 @@ runAoC y d = do
   riddle <- loadRiddle y d
   solve y d riddle
 
+runAoCExample :: (MonadIO m) => Year -> Day -> m (Either Text Solution)
+runAoCExample y d = do
+  riddle <- loadExample y d
+  solve y d riddle
+
 solve :: (MonadIO m) => Year -> Day -> Riddle -> m (Either Text Solution)
 solve Y2023 = Y2023.solve
 solve y = \_ _ -> pure $ Left $ show y <> ": not implementedi"

src/AoC/Y2023/D05.hs

@@ -1,6 +1,46 @@
-module AoC.Y2023.D05 (solve) where
+module AoC.Y2023.D05 where
 
+import AoC.Parser
 import AoC.Riddle
+import Text.Megaparsec (choice, sepBy1)
+
+import Text.Megaparsec.Char (eol, space1, string)
+import Text.Megaparsec.Char.Lexer qualified as L
+
+newtype Seeds = Seeds [Int]
+  deriving newtype (Show)
+
+-- | Parse a list of seeds
+--
+-- >>> parseText pSeeds "seeds: 79 14 55 13"
+-- Right [79,14,55,13]
+pSeeds :: Parser Seeds
+pSeeds = Seeds <$> (string "seeds: " *> L.decimal `sepBy1` ws)
+
+newtype Mapping = Mapping [((Int, Int), (Int, Int))]
+
+pRanges :: Parser [((Int, Int), (Int, Int))]
+pRanges = do
+  pRange `sepBy1` eol
+ where
+  pRange = do
+    x0 <- L.decimal <* space1
+    x1 <- L.decimal <* space1
+    n <- L.decimal
+    pure ((x0, x0 + n), (x1, x1 + n))
+
+pMapping :: Parser Mapping
+pMapping = do
+  _ <-
+    choice
+      [ string "soil-to-fertilizer map:"
+      , string "fertilizer-to-water map:"
+      , string "water-to-light map:"
+      , string "light-to-temperature map:"
+      , string "light-to-temperature map:"
+      ]
+      <* eol
+  Mapping . fromList <$> pRanges `sepBy1` eol
 
 solve :: (MonadIO m) => Text -> m (Either Text Solution)
 solve _ = pure $ Left "not yet implemented"