advent14parallel.hs

   1 import Data.List (nub, tails)
   2 import Data.ByteString.Char8 (pack)
   3 import Crypto.Hash (hash, Digest, MD5)
   4 import Control.Parallel.Strategies (withStrategy, parBuffer, rdeepseq)
   5
   6 salt = "yjdafjpo"
   7 -- salt = "abc"
   8
   9 stretch_factor = [1..2016]
  10 -- stretch_factor = [1..100]
  11
  12 main :: IO ()
  13 main = do
  14         part1
  15         part2
  16
  17 part1 :: IO ()
  18 part1 = print $ head $ drop 63 $ filter (\i -> possibleKey sq i && confirmKey sq i) [0..]
  19     where sq = md5sequence
  20
  21 part2 :: IO ()
  22 part2 = print $ head $ drop 63 $ filter (\i -> possibleKey sq i && confirmKey sq i) [0..]
  23     where sq = md5sequenceS
  24
  25 getHash :: String -> String
  26 getHash bs = show (hash $ pack bs :: Digest MD5)
  27
  28 md5sequence :: [String]
  29 -- md5sequence = [makeMd5 i | i <- [0..]]
  30 md5sequence = withStrategy (parBuffer 100 rdeepseq) $ map (makeMd5) [0..]
  31     where makeMd5 i = getHash (salt ++ show i)
  32
  33 md5sequenceS :: [String]
  34 -- md5sequenceS = [makeMd5 i | i <- [0..]]
  35 md5sequenceS = withStrategy (parBuffer 100 rdeepseq) $ map (makeMd5) [0..]
  36     where makeMd5 i = stretch $ getHash (salt ++ show i)
  37           stretch h0 = foldr (\_ h -> getHash h) h0 stretch_factor
  38
  39 possibleKey :: [String] -> Int-> Bool
  40 possibleKey s = not . null . repeats 3 . ((!!) s)
  41
  42 confirmKey :: [String] -> Int -> Bool
  43 confirmKey s i = any (confirmation) $ take 1000 $ drop (i+1) s
  44     where c = head $ repeats 3 $ s!!i
  45           confirmation m = c `elem` (repeats 5 m)
  46
  47 repeats :: Int -> String -> [String]
  48 repeats n = filter (null . tail) . map (nub) . substrings n
  49
  50 substrings :: Int -> [a] -> [[a]]
  51 substrings l = filter (\s -> (length s) == l) . map (take l) . tails