2022-24 in haskell

5 files changed, 233 insertions, 0 deletions

diff --git a/2022/24-Blizzard_Basin/example b/2022/24-Blizzard_Basin/example
new file mode 100644
index 0000000..158014b
--- /dev/null
+++ b/2022/24-Blizzard_Basin/example
@@ -0,0 +1,7 @@
+#.#####
+#.....#
+#>....#
+#.....#
+#...v.#
+#.....#
+#####.#
diff --git a/2022/24-Blizzard_Basin/example2 b/2022/24-Blizzard_Basin/example2
new file mode 100644
index 0000000..685dc4f
--- /dev/null
+++ b/2022/24-Blizzard_Basin/example2
@@ -0,0 +1,6 @@
+#.######
+#>>.<^<#
+#.<..<<#
+#>v.><>#
+#<^v^^>#
+######.#
diff --git a/2022/24-Blizzard_Basin/first.hs b/2022/24-Blizzard_Basin/first.hs
new file mode 100644
index 0000000..b0e5f00
--- /dev/null
+++ b/2022/24-Blizzard_Basin/first.hs
@@ -0,0 +1,94 @@
+-- very slow with runghc, use ghc -O3 -o first first.hs
+-- requires cabal install --lib megaparsec parser-combinators unordered-containers
+module Main (main) where
+import Control.Monad (void, when)
+import Data.Functor
+import Data.List qualified as L
+import Data.Map qualified as M
+import Data.Set qualified as S
+import Data.Void (Void)
+import Text.Megaparsec
+import Text.Megaparsec.Char
+import System.Exit (die)
+
+import Debug.Trace
+
+exampleExpectedOutput = 18
+
+data Direction = N | S | E | W deriving Show
+data Blizzard = Blizzard Int Int Direction deriving Show
+data Input = Input { blizzards :: [Blizzard]
+                   , height :: Int
+                   , width :: Int
+                   , xend :: Int
+                   , xstart :: Int
+                   } deriving Show
+
+type Parser = Parsec Void String
+
+findBlizzards :: (Int, [Blizzard]) -> String -> (Int, [Blizzard])
+findBlizzards (y, acc) line = (y+1, snd $ L.foldl' findBlizzards' (0, acc) line)
+  where
+    findBlizzards' :: (Int, [Blizzard]) -> Char -> (Int, [Blizzard])
+    findBlizzards' (x, acc) '#' = (x+1, acc)
+    findBlizzards' (x, acc) '.' = (x+1, acc)
+    findBlizzards' (x, acc) '^' = (x+1, Blizzard x y N : acc)
+    findBlizzards' (x, acc) 'v' = (x+1, Blizzard x y S : acc)
+    findBlizzards' (x, acc) '>' = (x+1, Blizzard x y E : acc)
+    findBlizzards' (x, acc) '<' = (x+1, Blizzard x y W : acc)
+
+parseMapLine :: Parser String
+parseMapLine = some (char '.' <|> char '#' <|> char '>' <|> char '<' <|> char '^' <|> char 'v') <* eol
+
+parseInput' :: Parser Input
+parseInput' = do
+  lines <- some parseMapLine <* eof
+  let height = length lines
+      start = head lines
+      width = length start
+      Just xend = L.elemIndex '.' $ last lines
+      Just xstart = L.elemIndex '.' start
+      blizzards = snd $ L.foldl' findBlizzards (0, []) lines
+  return $ Input blizzards height width xend xstart
+
+parseInput :: String -> IO Input
+parseInput filename = do
+  input <- readFile filename
+  case runParser parseInput' filename input of
+    Left bundle -> die $ errorBundlePretty bundle
+    Right input' -> return input'
+
+type Position = (Int, Int)
+
+compute :: Input -> Int
+compute (Input blizzards height width xend xstart) = compute' 0 $ S.singleton (xstart, 0)
+  where
+    boundaries :: S.Set Position
+    boundaries = S.fromList (([(x, y)|x<-[0..width-1], y<-[0, height-1]] L.\\ [(xstart, 0), (xend, height-1)]) -- north and south walls
+              ++ [(x, y)|x<-[0, width-1], y<-[1..height-2]] -- east and west walls
+              ++ [(xstart, -1), (xend, height)]) -- to prevent escaping to the north and south
+    compute' :: Int -> S.Set Position -> Int
+    compute' i pos | (xend, height-1) `L.elem` pos = i
+                   | otherwise = compute' (i+1) (step (i+1) pos)
+    step :: Int -> S.Set Position -> S.Set Position
+    step i = L.foldl' eval S.empty
+      where
+        eval :: S.Set Position -> Position -> S.Set Position
+        eval acc pos = S.union acc ((candidates pos S.\\ boundaries) S.\\ blizzards' i)
+          where
+            candidates :: Position -> S.Set Position
+            candidates (x, y) = S.fromList [(x-1, y), (x, y), (x+1, y), (x, y-1), (x, y+1)]
+    blizzards' i = S.fromList $ map (evalBlizzards i) blizzards
+    evalBlizzards :: Int -> Blizzard -> Position
+    evalBlizzards i (Blizzard x y N) = (x, ((y - i - 1) `mod` (height-2)) + 1)
+    evalBlizzards i (Blizzard x y S) = (x, ((y + i - 1) `mod` (height-2)) + 1)
+    evalBlizzards i (Blizzard x y E) = (((x + i - 1) `mod` (width-2)) + 1, y)
+    evalBlizzards i (Blizzard x y W) = (((x - i - 1) `mod` (width-2)) + 1, y)
+
+main :: IO ()
+main = do
+  example <- parseInput "example2"
+  let exampleOutput = compute example
+  when  (exampleOutput /= exampleExpectedOutput)  (die $ "example failed: got " ++ show exampleOutput ++ " instead of " ++ show exampleExpectedOutput)
+  input <- parseInput "input"
+  print $ compute input
diff --git a/2022/24-Blizzard_Basin/input b/2022/24-Blizzard_Basin/input
new file mode 100644
index 0000000..285925a
--- /dev/null
+++ b/2022/24-Blizzard_Basin/input
@@ -0,0 +1,27 @@
+#.########################################################################################################################
+#<>v^<vv<v<><.^v><<.>v><<^^<v..<>.v^>^v<^><vv>.>^v>^>>v^v>><^><><<^><^>.^>^<vv>v>^>>^<^v.^<^v<.><.v><<.^v^.^<v^v<<vv><<v>#
+#<>.vv^^vv<^v.^><^v<>>.<<<.^<^<>v<v<<>v>^vv..<<.^>^>>>.<>>^.^<^<<<^<>vv>.<<><^>.^>.vv^^v..v^<v^<vv.^.>v<^<^.<>^^v>^>v^<^>#
+#<<>v>v>v.^<><^><>^>.v<<>.^v.v<<v<^^v>v<^^<<>^>vv<vvv>^v^.<>>^^^^<><vvv<v^>^<vv.><..><^>^<<^><^.v>>^>>>v>v>>vv^v<<.<v^<^>#
+#<^.vv><^>^^>v<.>^vvv>v^v>><v>><v<><^.>v^v<v<<<>v.^>>^>v>^.>><<<v.^^^v^.v>^^vv^<<.v^<^v.v<<>><><vv.vv<^..<vv^.^<>>>.<<^^>#
+#<^<v<.>vvvvvv^>>.^v>.<<v^^^><^<^^<^>v><>>><>>vv^v><^>v>>v.^>>>v^v^^^.^^>^v<.v^>^^v<vv.<.<^v>vv^v>^v>>v<^^>>^^<><^>v<v>.>#
+#<vvvv<<^<v^vvv<.^<vv>.>v<v><<^v>^^<^v<^>vv^.<^vvv<^>^^vv^.v.^^..><<>^.>...^<<^>^^<^vvv>.^<>>^.v^v.^<>v^<vvvv>^.<>v>><v<>#
+#>.^>.vv^<^^<v><><<>>>vv>.<><^^<>>v><<>>v^vv.>^.>v^^<^<^.>>v<<<vv<<>>.<^<><.<<^v^><>.<>^<<.^>^v<>^^>><<>vv.v<>v^^>>>>>v><#
+#<.^<>.>.^>v><.^<>>>^^<^v^>^<^.>^^^v.<>vv><>v^v^v^^<^>^<<.v^>^v.<>.<^.>v><>>.<<v<^>>v>>>.^<><v<vv.<^^>^v<<<^^.<v<^>v>v^<<#
+#><^>.<<<^..>>>^>.>^<vv.<.v^><>>>^<.v<^^^><>v.>.v^v<^^v><^.^.><^^<>^^v<>><^<.v>><>>>>.>^v<^v^<<^v>>.v<^<>vv<>v>vv.^<<<v.<#
+#>.^^<<><v.>^^>>.^>^v>^>..>>>^v^<v^^^>v>>v>>v.^<>vv><>.<>vvvvv.vvv..><>v.vv<^v^v>^>^vv^<v<.^>>.>v^><<v>^v^>>.>^v><<^^^<v<#
+#.^<>>.v<>vv<vvv^^>vv><<.^>><^.v>>^v<.v^<^v^.<vvv^^>^^>^>>>.^.>vvv>>^^^^<^^v>^>v^<v><v^<><><<^v<<<><><<v^.vv><^vv^v<<vv<>#
+#<..vvv>><.v<^><v.v^^^v>^^v<<^v<>^><^v>^vvv^<^v>>^>>^<v>^<<^v^v.^vv>^><^v<^v^v>vv>^<^^^v>^^^<.>^v.v^<^>>^>^^^^^^vv<.v^^><#
+#<v><<v>>^v<>>v^^v<^v<<><<^><^<<^^>.<.^v>^>>v<>^><.^<<<.>^^v^vvv><<^>>^^<^^<><v.^v<<^..v^.<v>>^v.>^<^^v<<vvv^v<^<<<<<v>^>#
+#<v<<v^<^<^^v^vv<<<.>v<<><<^v^.^>><.v<^<v<^<<<<.<v^^vvv^>^^^>.><<><><<<^>v.>>>vv<.<v.><>^v^>^^^^.>v^<>.v>^.<v>v<^.v>vv<>>#
+#>v<v..<^v^<<<>><>>^<^v>>v>v^>vv^v<^.vv^vv>v<<<vv.v^.>^v><<v<vv>>^<.>vvv...v<^><>>.^v>v<^^>v^v<<>v>.^>><<<><<v^<v^.^v^>v>#
+#<<>^v>v>v<<<vvvv^^>v^..>..>^<>^>>><><<><v><^vv.>^v>v^v<<<vv><<.>><<<<<.<<<>^><v><vv^^v>^>>>><.^.^^>v<^<^>>.^>>^v.<>^>v>>#
+#>v<<<>^^>..^>>v.v^<><^>^^<<vv<<>>^<<>v^.<^><.v>>vv^v<v<^^v..>>^^^>^v>^v^^v^>^.<^>>>v^<><v>^.<>>^^<vv>>>^><^>>.<<>>v>vv<>#
+#<^^^..>>><>v>v>.>^.<.vv.vv<>v^vv<<^^>>v<^^<vv><^>><v>>>^^^><^^<.<^^>v>^^><v<vv^>vvv<^<..^>>>^v^v^^v>^^^.<.>v<^v><><>^^.>#
+#>^^>^^^^.<<.v^.><v<^^.<<<.><<><>.<<<^^><.>>..<>v^^^>^v<^>>.>v><^^vvv^>>^<v>v><^<>^<>>^^v>^.v>v<<>>>^v^vv<<<^..<>^><>>^>.#
+#.^<<<^^vv<.>v<.<>.>v.^..^^.>.vv.v>^>v.^.v<>v>>^^<^<^^^>>^>vvv.<^>><^>><^^>^>..^><.<v>.<^>^^v^v.>v<v^^><<>>vv^vv><v<>v^<>#
+#<vvv><<>v<^<^.>..^<.<v^v^v>.^<^vv^v>v<vvv<>><>vv.vvv<^><^^>><>vv>^^^><>^<^^><^>.>v<>^.vv<v<<v^^>v<v.^^^><>^<v^<>.>.^^v^>#
+#>v.^>..^>v>v>^^<^v>..>..^<.^..>>v<>.<>.<v>>>vv^<<>>>v<v^v^^vv<^vvvv<^v<^v<^^>>v>v><v><<v><v><^v<v>^>^^<>v.v<<^<.<><<<>.>#
+#>>v><..^^^.<v<^^<v<><<<<<^^^<>^^v^.>vv<v><<>>^^^<v^vv^v^<>...>^.<v><<^^v^..><>vv>v^>^v>.vv<v<^.<<<v^<^v^<<v^.<.^<.>v^<><#
+#>^v<..<>>v^v>v>v^v^<^<^^<..><v>^^>><<><>.^v.v<^>^<v><.^vv^.>v^>^v>^^v^>v<v^...><<<>><>>>^<vv<<^^^.<^vv^^^.v<vv<<<>>^><^<#
+#>><<v<>>>vv>>^^^v^^^>^>><v<>><^vv><>>>^.v^>^>^vv<>>..^v.^^^vvvv<><^><^v>vv<<^vv>^>v..<><.>^^^v.v>vvvv>>>><<vv<>.<v^<vv>>#
+########################################################################################################################.#
diff --git a/2022/24-Blizzard_Basin/second.hs b/2022/24-Blizzard_Basin/second.hs
new file mode 100644
index 0000000..d11f3f4
--- /dev/null
+++ b/2022/24-Blizzard_Basin/second.hs
@@ -0,0 +1,99 @@
+-- very slow with runghc, use ghc -O3 -o second second.hs
+-- requires cabal install --lib megaparsec parser-combinators unordered-containers
+module Main (main) where
+import Control.Monad (void, when)
+import Data.Functor
+import Data.List qualified as L
+import Data.Map qualified as M
+import Data.Set qualified as S
+import Data.Void (Void)
+import Text.Megaparsec
+import Text.Megaparsec.Char
+import System.Exit (die)
+
+import Debug.Trace
+
+exampleExpectedOutput = 54
+
+data Direction = N | S | E | W deriving Show
+data Blizzard = Blizzard Int Int Direction deriving Show
+data Input = Input { blizzards :: [Blizzard]
+                   , height :: Int
+                   , width :: Int
+                   , xend :: Int
+                   , xstart :: Int
+                   } deriving Show
+
+type Parser = Parsec Void String
+
+findBlizzards :: (Int, [Blizzard]) -> String -> (Int, [Blizzard])
+findBlizzards (y, acc) line = (y+1, snd $ L.foldl' findBlizzards' (0, acc) line)
+  where
+    findBlizzards' :: (Int, [Blizzard]) -> Char -> (Int, [Blizzard])
+    findBlizzards' (x, acc) '#' = (x+1, acc)
+    findBlizzards' (x, acc) '.' = (x+1, acc)
+    findBlizzards' (x, acc) '^' = (x+1, Blizzard x y N : acc)
+    findBlizzards' (x, acc) 'v' = (x+1, Blizzard x y S : acc)
+    findBlizzards' (x, acc) '>' = (x+1, Blizzard x y E : acc)
+    findBlizzards' (x, acc) '<' = (x+1, Blizzard x y W : acc)
+
+parseMapLine :: Parser String
+parseMapLine = some (char '.' <|> char '#' <|> char '>' <|> char '<' <|> char '^' <|> char 'v') <* eol
+
+parseInput' :: Parser Input
+parseInput' = do
+  lines <- some parseMapLine <* eof
+  let height = length lines
+      start = head lines
+      width = length start
+      Just xend = L.elemIndex '.' $ last lines
+      Just xstart = L.elemIndex '.' start
+      blizzards = snd $ L.foldl' findBlizzards (0, []) lines
+  return $ Input blizzards height width xend xstart
+
+parseInput :: String -> IO Input
+parseInput filename = do
+  input <- readFile filename
+  case runParser parseInput' filename input of
+    Left bundle -> die $ errorBundlePretty bundle
+    Right input' -> return input'
+
+type Position = (Int, Int)
+
+compute :: Input -> Int
+compute (Input blizzards height width xend xstart) = let firstTrip = compute' 0 $ S.singleton (xstart, 0)
+                                                         secondTrip = compute'' firstTrip $ S.singleton (xend, height - 1)
+                                                     in compute' secondTrip $ S.singleton (xstart, 0)
+  where
+    boundaries :: S.Set Position
+    boundaries = S.fromList (([(x, y)|x<-[0..width-1], y<-[0, height-1]] L.\\ [(xstart, 0), (xend, height-1)]) -- north and south walls
+              ++ [(x, y)|x<-[0, width-1], y<-[1..height-2]] -- east and west walls
+              ++ [(xstart, -1), (xend, height)]) -- to prevent escaping to the north and south
+    compute' :: Int -> S.Set Position -> Int
+    compute' i pos | (xend, height-1) `L.elem` pos = i
+                   | otherwise = compute' (i+1) (step (i+1) pos)
+    compute'' :: Int -> S.Set Position -> Int
+    compute'' i pos | (xstart, 0) `L.elem` pos = i
+                    | otherwise = compute'' (i+1) (step (i+1) pos)
+    step :: Int -> S.Set Position -> S.Set Position
+    step i = L.foldl' eval S.empty
+      where
+        eval :: S.Set Position -> Position -> S.Set Position
+        eval acc pos = S.union acc ((candidates pos S.\\ boundaries) S.\\ blizzards' i)
+          where
+            candidates :: Position -> S.Set Position
+            candidates (x, y) = S.fromList [(x-1, y), (x, y), (x+1, y), (x, y-1), (x, y+1)]
+    blizzards' i = S.fromList $ map (evalBlizzards i) blizzards
+    evalBlizzards :: Int -> Blizzard -> Position
+    evalBlizzards i (Blizzard x y N) = (x, ((y - i - 1) `mod` (height-2)) + 1)
+    evalBlizzards i (Blizzard x y S) = (x, ((y + i - 1) `mod` (height-2)) + 1)
+    evalBlizzards i (Blizzard x y E) = (((x + i - 1) `mod` (width-2)) + 1, y)
+    evalBlizzards i (Blizzard x y W) = (((x - i - 1) `mod` (width-2)) + 1, y)
+
+main :: IO ()
+main = do
+  example <- parseInput "example2"
+  let exampleOutput = compute example
+  when  (exampleOutput /= exampleExpectedOutput)  (die $ "example failed: got " ++ show exampleOutput ++ " instead of " ++ show exampleExpectedOutput)
+  input <- parseInput "input"
+  print $ compute input