Day fifteen

day-15-haskell/.gitignore

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+.stack-work/
+*~

day-15-haskell/Setup.hs

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+import Distribution.Simple
+main = defaultMain

day-15-haskell/app/Main.hs

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+module Main (main) where
+
+import System.Environment.Blank ( getArgs )
+import Lib (task1, task2)
+
+main :: IO ()
+main = do
+  args <- getArgs
+  case args of
+    ["1", file] -> do
+      input <- readFile file
+      result <- task1 input
+      print result
+    ["2", file] -> do
+      input <- readFile file
+      result <- task2 input
+      print result
+    _ -> error "Usage: <1|2> <input file>"

day-15-haskell/day15-haskell.cabal

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+cabal-version: 2.2
+
+-- This file has been generated from package.yaml by hpack version 0.37.0.
+--
+-- see: https://github.com/sol/hpack
+
+name:           day15-haskell
+version:        0.1.0.0
+homepage:       https://github.com/Siphalor/day15-haskell#readme
+bug-reports:    https://github.com/Siphalor/day15-haskell/issues
+author:         Siphalor
+maintainer:     info@siphalor.de
+copyright:      Siphalor
+license:        BSD-3-Clause
+build-type:     Simple
+
+source-repository head
+  type: git
+  location: https://github.com/Siphalor/day15-haskell
+
+library
+  exposed-modules:
+      Lib
+  hs-source-dirs:
+      src
+  ghc-options: -Wall -Wcompat -Widentities -Wincomplete-record-updates -Wincomplete-uni-patterns -Wmissing-home-modules -Wpartial-fields -Wredundant-constraints
+  build-depends:
+      base >=4.7 && <5
+    , containers
+    , flow
+  default-language: Haskell2010
+
+executable day15-haskell-exe
+  main-is: Main.hs
+  hs-source-dirs:
+      app
+  ghc-options: -Wall -Wcompat -Widentities -Wincomplete-record-updates -Wincomplete-uni-patterns -Wmissing-home-modules -Wpartial-fields -Wredundant-constraints -threaded -rtsopts -with-rtsopts=-N
+  build-depends:
+      base >=4.7 && <5
+    , day15-haskell
+  default-language: Haskell2010
+
+test-suite day15-haskell-test
+  type: exitcode-stdio-1.0
+  main-is: Spec.hs
+  hs-source-dirs:
+      test
+  ghc-options: -Wall -Wcompat -Widentities -Wincomplete-record-updates -Wincomplete-uni-patterns -Wmissing-home-modules -Wpartial-fields -Wredundant-constraints -threaded -rtsopts -with-rtsopts=-N
+  build-depends:
+      base >=4.7 && <5
+    , day15-haskell
+  default-language: Haskell2010

day-15-haskell/package.yaml

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+name:                day15-haskell
+version:             0.1.0.0
+github:              "Siphalor/day15-haskell"
+license:             BSD-3-Clause
+author:              "Siphalor"
+maintainer:          "info@siphalor.de"
+copyright:           "Siphalor"
+spec-version:        0.36.0
+
+dependencies:
+- base >= 4.7 && < 5
+
+ghc-options:
+- -Wall
+- -Wcompat
+- -Widentities
+- -Wincomplete-record-updates
+- -Wincomplete-uni-patterns
+- -Wmissing-home-modules
+- -Wpartial-fields
+- -Wredundant-constraints
+
+library:
+  source-dirs: src
+  dependencies:
+  - flow
+  - containers
+
+executables:
+  day15-haskell-exe:
+    main:                Main.hs
+    source-dirs:         app
+    ghc-options:
+    - -threaded
+    - -rtsopts
+    - -with-rtsopts=-N
+    dependencies:
+    - day15-haskell
+
+tests:
+  day15-haskell-test:
+    main:                Spec.hs
+    source-dirs:         test
+    ghc-options:
+    - -threaded
+    - -rtsopts
+    - -with-rtsopts=-N
+    dependencies:
+    - day15-haskell

day-15-haskell/src/Lib.hs

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+{-# LANGUAGE NamedFieldPuns #-}
+
+module Lib where
+
+import Control.Monad (join)
+import qualified Data.Map.Strict as Map
+import Data.Maybe (fromMaybe, listToMaybe, maybeToList)
+import Flow
+import Text.ParserCombinators.ReadP
+
+type IntType = Int
+
+data Vec2 = Vec2 IntType IntType
+  deriving (Eq, Ord, Show)
+vAdd :: Vec2 -> Vec2 -> Vec2
+vAdd (Vec2 aX aY) (Vec2 bX bY) = Vec2 (aX + bX) (aY + bY)
+data Tile = Wall | Box
+  deriving (Eq, Ord, Show)
+data World = World { wMap :: Map.Map Vec2 Tile, wRobot :: Vec2 }
+data Direction = DUp | DRight | DDown | DLeft
+  deriving (Eq, Ord, Show)
+dVec :: Direction -> Vec2
+dVec DUp = Vec2 0 (-1)
+dVec DRight = Vec2 1 0
+dVec DDown = Vec2 0 1
+dVec DLeft = Vec2 (-1) 0
+type Instruction = Direction
+
+task1 :: String -> IO IntType
+task1 input =
+  let (world, instructions) = parseFile input
+      finalWorld = followInstructions world instructions
+  in do
+    putStrLn $ showWorld finalWorld
+    wMap finalWorld |> Map.filter ((==) Box) |> Map.keys |> map gps |> sum |> return
+
+task2 :: String -> IO IntType
+task2 _ = return 2
+
+gps :: Vec2 -> IntType
+gps (Vec2 x y) = 100 * y + x
+
+followInstructions :: World -> [Instruction] -> World
+followInstructions world [] = world
+followInstructions world (instruction:instructions) =
+  followInstructions (followInstruction world instruction) instructions
+  where
+    followInstruction :: World -> Instruction -> World
+    followInstruction world instruction = fromMaybe world $ tryMoveRobot world $ dVec instruction
+
+    tryMoveRobot :: World -> Vec2 -> Maybe World
+    tryMoveRobot World { wMap, wRobot } vector =
+      let target = wRobot `vAdd` vector
+          targetMap = World { wMap, wRobot = target }
+      in case wMap Map.!? target of
+        Nothing -> return targetMap
+        Just Wall -> Nothing
+        Just Box -> tryMoveBox targetMap target vector
+
+    tryMoveBox :: World -> Vec2 -> Vec2 -> Maybe World
+    tryMoveBox world@World { wMap } from vector =
+      case wMap Map.!? target of
+        Nothing -> Just $ move world
+        Just Wall -> Nothing
+        Just Box -> fmap move $ tryMoveBox world target vector
+
+      where
+        target :: Vec2
+        target = from `vAdd` vector
+
+        move :: World -> World
+        move World { wMap, wRobot } = World { wMap = wMap |> Map.delete from |> Map.insert target Box, wRobot }
+
+showWorld :: World -> String
+showWorld World { wMap, wRobot } =
+  let Vec2 maxX maxY = Map.keys wMap |> maximum
+  in map (\y -> map (\x -> showTile (Vec2 x y)) [0..maxX] ++ "\n") [0..maxY] |> join
+  where
+    showTile :: Vec2 -> Char
+    showTile pos
+      | wRobot == pos = '@'
+      | otherwise = case wMap Map.!? pos of
+        Nothing -> '.'
+        Just Wall -> '#'
+        Just Box -> 'O'
+
+parseFile :: String -> (World, [Instruction])
+parseFile input = case readP_to_S parse input of
+  [] -> error "Failed to parse input"
+  ((r,_):_) -> r
+  where
+    parse :: ReadP (World, [Instruction])
+    parse = do
+      world <- parseWorld
+      _ <- munch isNewLine
+      instructions <- parseInstructions
+      _ <- munch isNewLine
+      _ <- eof
+      return (world, instructions)
+
+parseWorld :: ReadP World
+parseWorld = do
+  ls <- many1 line
+  return $ linesToWorld ls
+
+    where
+      line :: ReadP String
+      line = do
+        chars <- munch1 isMapTile
+        _ <- satisfy isNewLine
+        return chars
+      
+      isMapTile :: Char -> Bool
+      isMapTile c = any ((==) c) ['#', '@', 'O', '.']
+
+      linesToWorld :: [String] -> World
+      linesToWorld ls =
+        let enumerated = enumerateChars ls
+            robot = enumerated |> filter (\(_, c) -> c == '@') |> listToMaybe |> fmap (\(pos, _) -> pos) |> expectJust "No robot found"
+            worldMap = enumerated |> map (\(pos, c) -> toTile c |> fmap (\tile -> (pos, tile)) |> maybeToList) |> join |> Map.fromList
+        in World { wMap = worldMap, wRobot = robot }
+
+      enumerateChars :: [String] -> [(Vec2, Char)]
+      enumerateChars ls = zip [0..] ls |> map (\(y, l) -> zip [0..] l |> map (\(x, c) -> (Vec2 x y, c))) |> join
+
+      toTile :: Char -> Maybe Tile
+      toTile '#' = Just Wall
+      toTile 'O' = Just Box
+      toTile _ = Nothing
+
+parseInstructions :: ReadP [Instruction]
+parseInstructions = many1 parseInstruction
+  where
+    parseInstruction :: ReadP Instruction
+    parseInstruction = do
+      munch isNewLine
+      c <- get
+      case c of
+        '^' -> return DUp
+        '>' -> return DRight
+        'v' -> return DDown
+        '<' -> return DLeft
+        _ -> pfail
+
+isNewLine :: Char -> Bool
+isNewLine = (==) '\n'
+
+expectJust :: String -> Maybe a -> a
+expectJust _ (Just value) = value
+expectJust message Nothing = error message
+

day-15-haskell/stack.yaml

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+# This file was automatically generated by 'stack init'
+#
+# Some commonly used options have been documented as comments in this file.
+# For advanced use and comprehensive documentation of the format, please see:
+# https://docs.haskellstack.org/en/stable/yaml_configuration/
+
+# A 'specific' Stackage snapshot or a compiler version.
+# A snapshot resolver dictates the compiler version and the set of packages
+# to be used for project dependencies. For example:
+#
+# snapshot: lts-22.28
+# snapshot: nightly-2024-07-05
+# snapshot: ghc-9.6.6
+#
+# The location of a snapshot can be provided as a file or url. Stack assumes
+# a snapshot provided as a file might change, whereas a url resource does not.
+#
+# snapshot: ./custom-snapshot.yaml
+# snapshot: https://example.com/snapshots/2024-01-01.yaml
+snapshot:
+  url: https://raw.githubusercontent.com/commercialhaskell/stackage-snapshots/master/lts/23/0.yaml
+
+# User packages to be built.
+# Various formats can be used as shown in the example below.
+#
+# packages:
+# - some-directory
+# - https://example.com/foo/bar/baz-0.0.2.tar.gz
+#   subdirs:
+#   - auto-update
+#   - wai
+packages:
+- .
+# Dependency packages to be pulled from upstream that are not in the snapshot.
+# These entries can reference officially published versions as well as
+# forks / in-progress versions pinned to a git hash. For example:
+#
+# extra-deps:
+# - acme-missiles-0.3
+# - git: https://github.com/commercialhaskell/stack.git
+#   commit: e7b331f14bcffb8367cd58fbfc8b40ec7642100a
+#
+# extra-deps: []
+
+# Override default flag values for project packages and extra-deps
+# flags: {}
+
+# Extra package databases containing global packages
+# extra-package-dbs: []
+
+# Control whether we use the GHC we find on the path
+# system-ghc: true
+#
+# Require a specific version of Stack, using version ranges
+# require-stack-version: -any # Default
+# require-stack-version: ">=3.1"
+#
+# Override the architecture used by Stack, especially useful on Windows
+# arch: i386
+# arch: x86_64
+#
+# Extra directories used by Stack for building
+# extra-include-dirs: [/path/to/dir]
+# extra-lib-dirs: [/path/to/dir]
+#
+# Allow a newer minor version of GHC than the snapshot specifies
+# compiler-check: newer-minor

day-15-haskell/stack.yaml.lock

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+# This file was autogenerated by Stack.
+# You should not edit this file by hand.
+# For more information, please see the documentation at:
+#   https://docs.haskellstack.org/en/stable/lock_files
+
+packages: []
+snapshots:
+- completed:
+    sha256: 9444fadfa30b67a93080254d53872478c087592ad64443e47c546cdcd13149ae
+    size: 678857
+    url: https://raw.githubusercontent.com/commercialhaskell/stackage-snapshots/master/lts/23/0.yaml
+  original:
+    url: https://raw.githubusercontent.com/commercialhaskell/stackage-snapshots/master/lts/23/0.yaml

day-15-haskell/test/Spec.hs

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+main :: IO ()
+main = putStrLn "Test suite not yet implemented"