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