diff options
Diffstat (limited to '')
| -rw-r--r-- | 2024/16-Reindeer_Maze/example | 17 | ||||
| -rw-r--r-- | 2024/16-Reindeer_Maze/first.hs | 90 | ||||
| -rw-r--r-- | 2024/16-Reindeer_Maze/input | 141 | ||||
| -rw-r--r-- | 2024/16-Reindeer_Maze/second.hs | 94 |
4 files changed, 342 insertions, 0 deletions
diff --git a/2024/16-Reindeer_Maze/example b/2024/16-Reindeer_Maze/example new file mode 100644 index 0000000..bc61c57 --- /dev/null +++ b/2024/16-Reindeer_Maze/example @@ -0,0 +1,17 @@ +################# +#...#...#...#..E# +#.#.#.#.#.#.#.#.# +#.#.#.#...#...#.# +#.#.#.#.###.#.#.# +#...#.#.#.....#.# +#.#.#.#.#.#####.# +#.#...#.#.#.....# +#.#.#####.#.###.# +#.#.#.......#...# +#.#.###.#####.### +#.#.#...#.....#.# +#.#.#.#####.###.# +#.#.#.........#.# +#.#.#.#########.# +#S#.............# +################# diff --git a/2024/16-Reindeer_Maze/first.hs b/2024/16-Reindeer_Maze/first.hs new file mode 100644 index 0000000..23d1951 --- /dev/null +++ b/2024/16-Reindeer_Maze/first.hs @@ -0,0 +1,90 @@ +-- requires cabal install --lib megaparsec parser-combinators heap vector +module Main (main) where + +import Control.Monad (void, when) +import Data.Functor +import qualified Data.Heap as H +import qualified Data.List as L +import qualified Data.Map as M +import qualified Data.Vector as V +import Data.Void (Void) +import Text.Megaparsec +import Text.Megaparsec.Char + +exampleExpectedOutput = 11048 + +data Tile = Wall | Floor | Start | End deriving (Eq, Show) +type Line = V.Vector Tile +type Input = V.Vector Line + +type Parser = Parsec Void String + +parseTile :: Parser Tile +parseTile = char '#' $> Wall + <|> char '.' $> Floor + <|> char 'E' $> End + <|> char 'S' $> Start + +parseLine :: Parser Line +parseLine = do + line <- some parseTile <* eol + return $ V.generate (length line) (line !!) + +parseInput' :: Parser Input +parseInput' = do + line <- some parseLine <* eof + return $ V.generate (length line) (line !!) + +parseInput :: String -> IO Input +parseInput filename = do + input <- readFile filename + case runParser parseInput' filename input of + Left bundle -> error $ errorBundlePretty bundle + Right input' -> return input' + +type Cost = Int +data Heading = N | S | E | W deriving (Eq, Show) +type Coord = (Int, Int) +data Position = Position Coord Heading Cost deriving Show +instance Ord Position where + compare (Position _ _ c1) (Position _ _ c2) = c1 `compare` c2 +instance Eq Position where + (Position _ _ c1) == (Position _ _ c2) = c1 == c2 +type Visited = M.Map Coord Int + +type Candidates = H.MinHeap Position + +compute :: Input -> Int +compute input = walk M.empty $ H.singleton (Position start E 0) + where + walk :: Visited -> Candidates -> Int + walk v h | t == End = c + | otherwise = walk v' $ H.union h' $ H.fromList $ nexts v' $ Position p d c + where + ([(Position p@(x, y) d c)], h') = H.splitAt 1 h + t = input V.! y V.! x + v' = case M.lookup p v of + Just c' -> if c < c' then M.insert p c v else v + Nothing -> M.insert p c v + nexts :: Visited -> Position -> [Position] + nexts v p = L.filter (valid v) $ candidates p + valid :: Visited -> Position -> Bool + valid v (Position p@(x, y) _ c) = input V.! y V.! x /= Wall && case M.lookup p v of + Just c' -> c < c' + Nothing -> True + candidates :: Position -> [Position] + candidates (Position (x, y) N c) = [ Position (x-1, y) W (c+1001), Position (x+1, y) E (c+1001), Position (x, y-1) N (c+1) ] + candidates (Position (x, y) S c) = [ Position (x-1, y) W (c+1001), Position (x+1, y) E (c+1001), Position (x, y+1) S (c+1) ] + candidates (Position (x, y) E c) = [ Position (x, y-1) N (c+1001), Position (x, y+1) S (c+1001), Position (x+1, y) E (c+1) ] + candidates (Position (x, y) W c) = [ Position (x, y-1) N (c+1001), Position (x, y+1) S (c+1001), Position (x-1, y) W (c+1) ] + height = V.length input + width = V.length (input V.! 0) + start = (1, height - 2) + +main :: IO () +main = do + example <- parseInput "example" + let exampleOutput = compute example + when (exampleOutput /= exampleExpectedOutput) (error $ "example failed: got " ++ show exampleOutput ++ " instead of " ++ show exampleExpectedOutput) + input <- parseInput "input" + print $ compute input diff --git a/2024/16-Reindeer_Maze/input b/2024/16-Reindeer_Maze/input new file mode 100644 index 0000000..f78f2b5 --- 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+#S..#.............#.......#...................#.............#...............#.........#...........#.........#...............................# +############################################################################################################################################# diff --git a/2024/16-Reindeer_Maze/second.hs b/2024/16-Reindeer_Maze/second.hs new file mode 100644 index 0000000..07d2219 --- /dev/null +++ b/2024/16-Reindeer_Maze/second.hs @@ -0,0 +1,94 @@ +-- requires cabal install --lib megaparsec parser-combinators heap vector +module Main (main) where + +import Control.Monad (void, when) +import Data.Functor +import qualified Data.Heap as H +import qualified Data.List as L +import qualified Data.Map as M +import qualified Data.Set as S +import qualified Data.Vector as V +import Data.Void (Void) +import Text.Megaparsec +import Text.Megaparsec.Char + +exampleExpectedOutput = 64 + +data Tile = Wall | Floor | Start | End deriving (Eq, Show) +type Line = V.Vector Tile +type Input = V.Vector Line + +type Parser = Parsec Void String + +parseTile :: Parser Tile +parseTile = char '#' $> Wall + <|> char '.' $> Floor + <|> char 'E' $> End + <|> char 'S' $> Start + +parseLine :: Parser Line +parseLine = do + line <- some parseTile <* eol + return $ V.generate (length line) (line !!) + +parseInput' :: Parser Input +parseInput' = do + line <- some parseLine <* eof + return $ V.generate (length line) (line !!) + +parseInput :: String -> IO Input +parseInput filename = do + input <- readFile filename + case runParser parseInput' filename input of + Left bundle -> error $ errorBundlePretty bundle + Right input' -> return input' + +type Cost = Int +data Heading = N | S | E | W deriving (Eq, Ord, Show) +type Coord = (Int, Int, Heading) +type Path = S.Set Coord +data Position = Position Coord Cost Path deriving (Eq, Show) +instance Ord Position where + compare (Position _ c1 _) (Position _ c2 _) = c1 `compare` c2 +type Visited = M.Map Coord Int + +type Candidates = H.MinHeap Position + +compute :: Input -> Int +compute input = S.size $ S.map (\(x, y, _) -> (x, y)) $ walk infinity M.empty $ H.singleton (Position start 0 S.empty) + where + walk :: Int -> Visited -> Candidates -> S.Set Coord + walk l v h | H.size h == 0 = S.empty + | c > l = walk l v' h' + | t == End = S.union s' $ walk c v' h' + | otherwise = walk l v' $ H.union h' $ H.fromList $ nexts v' $ Position p c s' + where + ([(Position p@(x, y, d) c s)], h') = H.splitAt 1 h + t = input V.! y V.! x + v' = case M.lookup p v of + Just c' -> if c < c' then M.insert p c v else v + Nothing -> M.insert p c v + s' = S.insert p s + nexts :: Visited -> Position -> [Position] + nexts v p = L.filter (valid v) $ candidates p + valid :: Visited -> Position -> Bool + valid v (Position p@(x, y, _) c _) = input V.! y V.! x /= Wall && case M.lookup p v of + Just c' -> c <= c' + Nothing -> True + candidates :: Position -> [Position] + candidates (Position (x, y, N) c s) = [ Position (x-1, y, W) (c+1001) s, Position (x+1, y, E) (c+1001) s, Position (x, y-1, N) (c+1) s ] + candidates (Position (x, y, S) c s) = [ Position (x-1, y, W) (c+1001) s, Position (x+1, y, E) (c+1001) s, Position (x, y+1, S) (c+1) s ] + candidates (Position (x, y, E) c s) = [ Position (x, y-1, N) (c+1001) s, Position (x, y+1, S) (c+1001) s, Position (x+1, y, E) (c+1) s ] + candidates (Position (x, y, W) c s) = [ Position (x, y-1, N) (c+1001) s, Position (x, y+1, S) (c+1001) s, Position (x-1, y, W) (c+1) s ] + height = V.length input + width = V.length (input V.! 0) + start = (1, height - 2, E) + infinity = maxBound :: Int + +main :: IO () +main = do + example <- parseInput "example" + let exampleOutput = compute example + when (exampleOutput /= exampleExpectedOutput) (error $ "example failed: got " ++ show exampleOutput ++ " instead of " ++ show exampleExpectedOutput) + input <- parseInput "input" + print $ compute input |