90 lines
2.3 KiB
Haskell
90 lines
2.3 KiB
Haskell
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module Day2.Main (main) where
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import Data.List
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import Data.Tuple
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import Data.Maybe
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import System.IO
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import Control.Monad
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main :: IO ()
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main = do
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putStrLn "Day 2"
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handle <- openFile "app/Day2/input" ReadMode
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contents <- hGetContents handle
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let r1 = part1 contents
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putStrLn $ "part 1: " ++ show r1
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let r2 = part2 contents
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putStrLn $ "part 2: " ++ show r2
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data Shape = Rock | Paper | Scissors
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deriving (Show, Eq)
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instance Read Shape where
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readsPrec _ "A" = [(Rock, "")]
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readsPrec _ "B" = [(Paper, "")]
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readsPrec _ "C" = [(Scissors, "")]
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readsPrec _ "X" = [(Rock, "")]
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readsPrec _ "Y" = [(Paper, "")]
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readsPrec _ "Z" = [(Scissors, "")]
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readsPrec _ _ = []
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instance Enum Shape where
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fromEnum Rock = 1
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fromEnum Paper = 2
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fromEnum Scissors = 3
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toEnum _ = error "nope"
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data Result = Loss | Tie | Win
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deriving (Show, Eq)
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instance Read Result where
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readsPrec _ "X" = [(Loss, "")]
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readsPrec _ "Y" = [(Tie, "")]
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readsPrec _ "Z" = [(Win, "")]
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readsPrec _ _ = []
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instance Enum Result where
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fromEnum Loss = 0
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fromEnum Tie = 3
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fromEnum Win = 6
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toEnum _ = error "nope"
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result :: Shape -> Shape -> Result
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result a b | a == b = Tie
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result Rock Paper = Loss
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result Rock Scissors = Win
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result Paper Rock = Win
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result Paper Scissors = Loss
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result Scissors Rock = Loss
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result Scissors Paper = Win
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parseInput :: String -> (String -> a) -> (String -> b) -> [(a, b)]
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parseInput contents lhs rhs = shapes
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where
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rounds = lines contents
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picks = map (\l -> ([l !! 0], [l !! 2])) rounds
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shapes = map (\(a,b) -> (lhs a, rhs b)) picks
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part1 :: String -> Int
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part1 contents = sum scoresResults + sum scoresPicks
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where
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rounds = parseInput contents (read :: String -> Shape) (read :: String -> Shape)
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scoresResults = map (fromEnum . (uncurry result) . swap) rounds
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scoresPicks = map (fromEnum . snd) rounds
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part2 :: String -> Int
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part2 contents = sum solutions + sum outcomes
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where
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rounds = parseInput contents (read :: String -> Shape) (read :: String -> Result)
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getResult o r = fromJust $ find (\p -> result p o == r) [Rock,Paper,Scissors]
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solutions = map (fromEnum . uncurry getResult) rounds
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outcomes = map (fromEnum . snd) rounds
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