130 lines
4.5 KiB
Haskell
Executable file
130 lines
4.5 KiB
Haskell
Executable file
#! /usr/bin/env -S"ANSWER=42" nix-shell
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#! nix-shell -p ghcid
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#! nix-shell -p "haskellPackages.ghcWithPackages (p: with p; [pretty-simple linear])"
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#! nix-shell -i "ghcid -c 'ghci' -T main"
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{-# OPTIONS_GHC -Wall -Wincomplete-uni-patterns #-}
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{-# OPTIONS_GHC -Wno-unused-top-binds -Wno-unused-imports -Wno-type-defaults #-}
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{-# OPTIONS_GHC -Wno-unused-matches #-}
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{-# LANGUAGE OverloadedStrings #-}
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{-# LANGUAGE DeriveAnyClass #-}
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import Debug.Trace (trace, traceShowId, traceShow)
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import Text.Pretty.Simple
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import Control.Monad
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import Linear.V2
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import Data.Monoid
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exampleData :: [ String ]
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exampleData =
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[ "F10"
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, "N3"
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, "F7"
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, "R90"
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, "F11"
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]
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data Ship = Ship { position :: V2 Double, orientation :: V2 Double }
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deriving (Show, Eq, Ord)
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-- At first, ship is at (0,0) facing East
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ship0 :: Ship
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ship0 = Ship (pure 0) (V2 1 0)
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-- At first, ship is at (0,0) facing East
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ship1 :: Ship
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ship1 = Ship (pure 0) (V2 10 1)
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-- instance Semigroup Ship
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-- where
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-- (<>) s1 s2 = Ship (getSum <$> ((Sum <$> (position s1)) <> (Sum <$> (position s2))))
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-- (getSum <$> ((Sum <$> (orientation s1)) <> (Sum <$> (orientation s2))))
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--
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-- instance Monoid Ship
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-- where
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-- mempty = Ship (pure 0) (pure 0)
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data Instruction = InsMoveForward !Double
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| InsMoveNorth !Double
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| InsMoveSouth !Double
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| InsMoveEast !Double
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| InsMoveWest !Double
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| InsTurnL !Double
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| InsTurnR !Double
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deriving (Show, Eq, Ord)
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parseIns :: String -> Instruction
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-- Action N means to move north by the given value.
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parseIns ('N':x) = InsMoveNorth (read x)
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-- Action S means to move south by the given value.
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parseIns ('S':x) = InsMoveSouth (read x)
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-- Action E means to move east by the given value.
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parseIns ('E':x) = InsMoveEast (read x)
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-- Action W means to move west by the given value.
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parseIns ('W':x) = InsMoveWest (read x)
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-- Action L means to turn left the given number of degrees.
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parseIns ('L':x) = InsTurnL (read x)
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-- Action R means to turn right the given number of degrees.
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parseIns ('R':x) = InsTurnR (read x)
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-- Action F means to move forward by the given value in the direction the ship is currently facing.
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parseIns ('F':x) = InsMoveForward (read x)
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parseIns e = trace ("Unknown instruction: "<>show e) undefined
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-- 2*PI rad = 360 deg
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-- 1 rad = 180/PI deg
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-- PI/180 rad = 1 deg
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runIns1 :: Ship -> Instruction -> Ship
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runIns1 s (InsMoveForward n) = s { position = (position s) + (pure n) * (orientation s) }
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runIns1 s (InsMoveNorth n) = s { position = (position s) + (pure n) * V2 0 1 }
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runIns1 s (InsMoveSouth n) = s { position = (position s) + (pure n) * V2 0 (-1) }
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runIns1 s (InsMoveEast n) = s { position = (position s) + (pure n) * V2 1 0 }
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runIns1 s (InsMoveWest n) = s { position = (position s) + (pure n) * V2 (-1) 0 }
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runIns1 s (InsTurnL n) = s { orientation = angle ((unangle (orientation s)) + n * pi / 180) }
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runIns1 s (InsTurnR n) = s { orientation = angle ((unangle (orientation s)) - n * pi / 180) }
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manhattanV2 :: (Num a) => V2 a -> a
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manhattanV2 (V2 x y) = (abs x) + (abs y)
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solvePart1 :: [String] -> Double
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solvePart1 = manhattanV2 . position . foldl runIns1 ship0 . map parseIns
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--------------------------------------------------------------------------------
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runIns2 :: Ship -> Instruction -> Ship
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runIns2 s (InsMoveForward n) = s { position = (position s) + (pure n) * (orientation s) }
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runIns2 s (InsMoveNorth n) = s { orientation = (orientation s) + V2 0 n }
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runIns2 s (InsMoveSouth n) = s { orientation = (orientation s) + V2 0 (-n) }
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runIns2 s (InsMoveEast n) = s { orientation = (orientation s) + V2 n 0 }
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runIns2 s (InsMoveWest n) = s { orientation = (orientation s) + V2 (-n) 0 }
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runIns2 s (InsTurnL n) = s { orientation = rotV2By (orientation s) n }
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runIns2 s (InsTurnR n) = s { orientation = rotV2By (orientation s) (-n) }
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rotV2By :: (Num a, Floating a) => V2 a -> a -> V2 a
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rotV2By (V2 x1 y1) n = V2 x y
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where
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x = cos a * x1 - sin a * y1
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y = sin a * x1 + cos a * y1
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a = n * pi / 180
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solvePart2 :: [String] -> Double
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solvePart2 = manhattanV2 . position . foldl runIns2 ship1 . map parseIns
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main :: IO ()
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main = do
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input <- lines <$> readFile "day12/input"
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putStrLn ":: Tests"
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pPrint exampleData
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pPrint $ map parseIns exampleData
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pPrint $ angle (90 * pi / 180)
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putStrLn ":: Day 12 - Part 1"
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pPrint $ solvePart1 exampleData
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pPrint $ solvePart1 input
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putStrLn ":: Day 12 - Part 2"
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pPrint $ solvePart2 exampleData
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pPrint $ solvePart2 input
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