30 lines
948 B
Haskell
30 lines
948 B
Haskell
module Day6_1 where
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import System.IO (openFile, IOMode (ReadMode), hClose, hGetContents)
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import Data.Text (splitOn, unpack, pack)
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import Prelude hiding (splitAt)
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import Data.List (group, sort)
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import Data.Map.Strict (toList, fromListWith)
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splitAt :: String -> String -> [String]
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splitAt delimiter str = map unpack $ splitOn (pack delimiter) $ pack str
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count :: [Int] -> [(Int, Int)]
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count fish = map (\x -> (head x, length x)) $ group $ sort fish
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grow :: (Int, Int) -> [(Int, Int)]
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grow fish
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| fst fish > 0 = [(fst fish - 1, snd fish)]
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| otherwise = [(6, snd fish), (8, snd fish)]
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sumFishes :: [(Int, Int)] -> [(Int, Int)]
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sumFishes = toList . fromListWith (+)
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main :: IO ()
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main = do
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input <- openFile "inputs/6.txt" ReadMode
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contents <- hGetContents input
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let fishies = map read $ splitAt "," contents :: [Int]
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print . sum . map snd . (!! 256) . iterate (sumFishes . concatMap grow) $ count fishies
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hClose input |