86 lines
2.8 KiB
Haskell
86 lines
2.8 KiB
Haskell
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-- everything stolen from http://learnyouahaskell.com/zippers#a-very-simple-file-system
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import Control.Monad
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data FS = FS [Inode]
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data Inode = Dir Name [Inode] | File Name Size deriving(Show)
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type Name = String
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type Size = Int
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data Command = Ls | Cd Name | CdUp | CdRoot deriving(Show)
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data Line = LineC Command | LineI Inode deriving(Show)
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parseCommand :: String -> Command
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parseCommand "ls" =Ls
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parseCommand "cd .." =CdUp
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parseCommand ('c':'d':' ':name) =(Cd name)
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parseInode :: String -> Inode
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parseInode ('d':'i':'r':' ': name) = Dir name []
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parseInode input = File (drop 1 $ dropWhile (/= ' ') input) (read $ takeWhile (/= ' ') input)
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parseEither :: String -> Line
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parseEither ('$':' ':command) =LineC $ parseCommand command
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parseEither input= LineI $ parseInode input
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foldFunction :: FSZipper -> Line -> FSZipper
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foldFunction zipper (LineC Ls) = zipper
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foldFunction zipper (LineC (Cd name)) = fsTo name zipper
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foldFunction zipper (LineC CdUp) = fsUp zipper
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foldFunction zipper (LineI inode) = fsNewInode inode zipper
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data FSCrumb = FSCrumb Name [Inode] [Inode] deriving (Show)
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type FSZipper = (Inode,[FSCrumb])
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fsUp :: FSZipper -> FSZipper
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fsUp (item, FSCrumb name ls rs:bs) = (Dir name (ls ++ [item] ++ rs), bs)
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fsUpToRoot :: FSZipper -> FSZipper
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fsUpToRoot ((Dir "/" content),bc) = ((Dir "/" content),bc)
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fsUpToRoot zipper = fsUp zipper
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fsTo :: Name -> FSZipper -> FSZipper
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fsTo name (Dir folderName items, bs) =
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let (ls, item:rs) = break (nameIs name) items
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in (item, FSCrumb folderName ls rs:bs)
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nameIs :: Name -> Inode -> Bool
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nameIs name (Dir folderName _) = name == folderName
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nameIs name (File fileName _) = name == fileName
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fsNewInode :: Inode -> FSZipper -> FSZipper
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fsNewInode newInode ((Dir name content),bc) = (Dir name (newInode:content),bc)
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initZipper :: FSZipper
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initZipper = (Dir "/" [],[])
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data InodeSize = DirS Size | FileS Size deriving(Show)
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getSize (DirS s)= s
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getSize (FileS s)=s
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flattenToSmallDirs :: Inode -> [InodeSize]
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flattenToSmallDirs (Dir _ children) =
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let childSizes =join $ map flattenToSmallDirs children
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currentSize=(sum $ map getSize $ childSizes) in
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(DirS currentSize):(filter isDir childSizes )
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flattenToSmallDirs (File _ size) = [FileS size]
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filterSmallDirs :: [InodeSize] -> [Size]
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filterSmallDirs ((DirS s):rest) = if (s<100000) then s:(filterSmallDirs rest) else filterSmallDirs rest
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filterSmallDirs ((FileS s):rest) = filterSmallDirs rest
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filterSmallDirs [] = []
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isDir (DirS s)=True
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isDir (FileS s)=False
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main = do
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content <- readFile "seven-input.txt"
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let statements = map parseEither $ drop 1 $ lines content
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let a = foldl foldFunction initZipper statements
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print $ sum $ filterSmallDirs $ flattenToSmallDirs $ fst $ fsUpToRoot a
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