68 lines
2.0 KiB
Haskell
68 lines
2.0 KiB
Haskell
{-# OPTIONS_GHC -Wno-type-defaults #-}
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module Day13
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( day13_1,
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day13_2,
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)
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where
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import Data.Char (isDigit)
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import Data.Either (fromRight)
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import Data.List (uncons)
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import Data.List.Split (chunksOf, splitOn)
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import Data.Matrix (Matrix, fromLists, rref, toList, zero)
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import Data.Maybe (fromJust, mapMaybe)
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isAlmostInt :: (RealFrac a) => a -> Bool
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isAlmostInt x =
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let diff = x - fromInteger (round x)
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in abs diff < 0.001
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multRes :: (Num a) => [a] -> [a]
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multRes [x, y, z] = [x, y, z + 10000000000000]
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multRes xs = xs
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getMatrix :: (Read a) => String -> Matrix a
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getMatrix s =
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let nValues = map (map read . splitOn ",") . splitOn ":" . drop 1 $ filter (\x -> isDigit x || x == ',' || x == ':') s
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eq1 = map (fst . fromJust . uncons) nValues
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eq2 = map last nValues
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in fromLists [eq1, eq2]
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getMatrix' :: (Num a, Read a) => String -> Matrix a
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getMatrix' s =
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let nValues = map (map read . splitOn ",") . splitOn ":" . drop 1 $ filter (\x -> isDigit x || x == ',' || x == ':') s
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eq1 = multRes $ map (fst . fromJust . uncons) nValues
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eq2 = multRes $ map last nValues
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in fromLists [eq1, eq2]
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solve :: (RealFrac a) => Matrix a -> Maybe [a]
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solve eqSystem =
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let rowEchelonList = toList . fromRight (zero 1 1) $ rref eqSystem
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solutions = [rowEchelonList !! 2, rowEchelonList !! 5]
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in if all isAlmostInt solutions
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then Just solutions
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else Nothing
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cost :: [Int] -> Int
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cost [x, y] = 3 * x + y
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cost _ = 0
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day13_1 :: IO ()
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day13_1 = do
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contents <- map concat . chunksOf 4 . lines <$> readFile "input/day13.txt"
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let eqSystems = map getMatrix contents
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solutions = (map . map) round $ mapMaybe solve eqSystems
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putStrLn $
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"Day 13, Puzzle 1 solution: "
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++ show (sum $ map cost solutions)
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day13_2 :: IO ()
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day13_2 = do
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contents <- map concat . chunksOf 4 . lines <$> readFile "input/day13.txt"
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let eqSystems = map getMatrix' contents
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solutions = (map . map) round $ mapMaybe solve eqSystems
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putStrLn $
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"Day 13, Puzzle 2 solution: "
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++ show (sum $ map cost solutions)
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