--- /dev/null
+{-# LANGUAGE OverloadedStrings #-}
+
+import Data.List (foldl') -- import the strict fold
+
+import Data.Text (Text)
+-- import qualified Data.Text as T
+import qualified Data.Text.IO as TIO
+
+import Data.Void (Void)
+
+import Text.Megaparsec -- hiding (State)
+import Text.Megaparsec.Char
+import qualified Text.Megaparsec.Char.Lexer as L
+import qualified Control.Applicative as CA
+
+
+-- number of steps
+type Distance = Int
+type Position = (Int, Int)
+
+-- the directions. See below for functions for turning
+data Direction = North | East | South | West
+ deriving (Enum, Show, Bounded, Eq)
+
+-- direction, easting, northing
+data Mowmaster = Mowmaster { direction :: Direction
+ , position :: Position
+ } deriving (Show, Eq)
+
+-- one instruction for the mowmaster
+data Instruction = Forward Distance
+ | Clockwise
+ | Anticlockwise
+ | Comment String
+ deriving (Show, Eq)
+
+
+main :: IO ()
+main = do
+ instruction_text <- TIO.readFile "data/01-mowmaster.txt"
+ let instructions = successfulParse instruction_text
+ print $ part1 instructions
+ print $ part2 instructions
+
+part1 :: [Instruction] -> Int
+part1 = length
+
+part2 :: [Instruction] -> Int
+part2 instructions = finalDistance $ executeAll instructions
+ where executeAll = foldl' execute initialMowmaster
+
+initialMowmaster = Mowmaster North (0, 0)
+
+
+-- Calculate manhattan distance from start to this state
+finalDistance :: Mowmaster -> Int
+finalDistance m = (abs e) + (abs n)
+ where (e, n) = position m
+
+
+-- Make one move
+execute :: Mowmaster -> Instruction -> Mowmaster
+execute m (Forward s) = m {position = forward s (direction m) (position m)}
+execute m Clockwise = m {direction = turnCW (direction m)}
+execute m Anticlockwise = m {direction = turnACW (direction m)}
+execute m _ = m
+
+-- Move in the current direction
+forward :: Int -> Direction -> Position -> Position
+forward s North (e, n) = (e, n+s)
+forward s South (e, n) = (e, n-s)
+forward s West (e, n) = (e-s, n)
+forward s East (e, n) = (e+s, n)
+
+
+-- | a `succ` that wraps
+turnCW :: (Bounded a, Enum a, Eq a) => a -> a
+turnCW dir | dir == maxBound = minBound
+ | otherwise = succ dir
+
+-- | a `pred` that wraps
+turnACW :: (Bounded a, Enum a, Eq a) => a -> a
+turnACW dir | dir == minBound = maxBound
+ | otherwise = pred dir
+
+
+-- Parse the input file
+
+type Parser = Parsec Void Text
+
+-- treat comment lines as whitespace
+sc :: Parser ()
+sc = L.space space1 lineComment CA.empty
+ where lineComment = L.skipLineComment "#"
+
+lexeme = L.lexeme sc
+integer = lexeme L.decimal
+symb = L.symbol sc
+
+-- instructions is some optional space followed by many instructions
+instrsP = optional sc *> many instrP
+instrP = forwardP <|> cwP <|> acwP
+
+-- parse each instruction
+forwardP = Forward <$> (symb "F" *> integer)
+cwP = Clockwise <$ symb "C"
+acwP = Anticlockwise <$ symb "A"
+
+successfulParse :: Text -> [Instruction]
+successfulParse input =
+ case parse instrsP "input" input of
+ Left _error -> [] -- TIO.putStr $ T.pack $ parseErrorPretty err
+ Right instrs -> instrs
\ No newline at end of file
import Data.List (foldl') -- import the strict fold
-- number of steps
-type Step = Int
+type Distance = Int
type Position = (Int, Int)
+-- the directions. See below for functions for turning
data Direction = North | East | South | West
deriving (Enum, Show, Bounded, Eq)
, position :: Position
} deriving (Show, Eq)
-data Instruction = Forward Step
+-- one instruction for the mowmaster
+data Instruction = Forward Distance
| Clockwise
| Anticlockwise
| Comment String
executeAll = foldl' execute initialMowmaster
-
-- Is this line a comment?
isComment :: String -> Bool
isComment ('#':_) = True
execute m Anticlockwise = m {direction = turnACW (direction m)}
execute m (Comment _) = m
+
-- Move in the current direction
forward :: Int -> Direction -> Position -> Position
forward s North (e, n) = (e, n+s)
forward s West (e, n) = (e-s, n)
forward s East (e, n) = (e+s, n)
-
-- | a `succ` that wraps
turnCW :: (Bounded a, Enum a, Eq a) => a -> a
turnCW dir | dir == maxBound = minBound
-# 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/
-
-# Resolver to choose 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:
-#
-# resolver: lts-3.5
-# resolver: nightly-2015-09-21
-# resolver: ghc-7.10.2
-# resolver: ghcjs-0.1.0_ghc-7.10.2
-#
-# 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.
-#
-# resolver: ./custom-snapshot.yaml
-# resolver: https://example.com/snapshots/2018-01-01.yaml
-resolver: lts-12.9
-
-# 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
-# - location:
-# git: https://github.com/commercialhaskell/stack.git
-# commit: e7b331f14bcffb8367cd58fbfc8b40ec7642100a
-# - location: https://github.com/commercialhaskell/stack/commit/e7b331f14bcffb8367cd58fbfc8b40ec7642100a
-# subdirs:
-# - auto-update
-# - wai
+flags: {}
+ghc-options:
+ $locals: -O2 -Wall -Wno-missing-signatures -threaded -rtsopts -with-rtsopts=-N
packages:
- .
-# Dependency packages to be pulled from upstream that are not in the resolver
-# using the same syntax as the packages field.
-# (e.g., acme-missiles-0.3)
-# extra-deps: []
-
-# Override default flag values for local packages and extra-deps
-# flags: {}
-
-# Extra package databases containing global packages
-# extra-package-dbs: []
-
-# Control whether we use the GHC we find on the path
-# system-ghc: true
-#
-# Require a specific version of stack, using version ranges
-# require-stack-version: -any # Default
-# require-stack-version: ">=1.7"
-#
-# Override the architecture used by stack, especially useful on Windows
-# arch: i386
-# arch: x86_64
-#
-# Extra directories used by stack for building
-# extra-include-dirs: [/path/to/dir]
-# extra-lib-dirs: [/path/to/dir]
-#
-# Allow a newer minor version of GHC than the snapshot specifies
-# compiler-check: newer-minor
-
-ghc-options:
- ! '$locals': -O2 -Wall -Wno-missing-signatures -threaded -rtsopts -with-rtsopts=-N
-
-extra-deps:
-- parsec-numbers-0.1.0
\ No newline at end of file
+extra-deps: []
+resolver: lts-12.9
main-is: task1.hs
default-language: Haskell2010
build-depends: base >= 4.7 && < 5
+
+executable task1-mpc
+ hs-source-dirs: src/task1
+ main-is: task1-mpc.hs
+ default-language: Haskell2010
+ build-depends: base >= 4.7 && < 5
+ , text
+ , megaparsec
projects / summerofcode2018soln.git / commitdiff