48 lines
1.2 KiB
Haskell
48 lines
1.2 KiB
Haskell
import Parsing (splitByString)
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main :: IO ()
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main = do
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input <- getContents
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let
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fish = parseFish input
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(putStrLn . show . solution1) fish
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(putStrLn . show . solution2) fish
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solution1 :: [Int] -> Int
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solution1 = sum . (simulateDays 79)
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solution2 :: [Int] -> Int
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solution2 = sum . (simulateDays 255)
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parseFish :: String -> [Int]
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parseFish = (map read) . (splitByString ",")
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initBuffer :: [Int] -> [Int]
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initBuffer initialFish = map occurrences [0..8]
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where
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occurrences x = length (filter (==x) initialFish)
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simulateDays :: Int -> [Int] -> [Int]
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simulateDays days initialFish = foldl tickDay (initBuffer initialFish) [0..days]
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where
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tickDay :: [Int] -> Int -> [Int]
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tickDay fish day = map fishMultiplier [0..length(fish)-1]
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where
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fishMultiplier :: Int -> Int
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fishMultiplier i
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| i == addedTo =
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(fish !! i) + (fish !! dayFish)
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| otherwise =
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fish !! i
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where
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dayFish = day `rem` 9
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addedTo = (dayFish + 7) `rem` 9
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-- Tests
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testInput = "3,4,3,1,2"
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testParsed = parseFish testInput
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test1 = solution1 (parseFish testInput) -- 5934
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test2 = solution2 (parseFish testInput) -- 26984457539
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