diff options
| -rw-r--r-- | Puzzle10.hs | 21 |
1 files changed, 21 insertions, 0 deletions
diff --git a/Puzzle10.hs b/Puzzle10.hs index 4909eac..fc01499 100644 --- a/Puzzle10.hs +++ b/Puzzle10.hs @@ -1,4 +1,7 @@ import Data.List.Split (splitOn) +import Data.Bits (xor) +import Numeric (showHex) +import Data.Char (ord) split3Ways :: [Int] -> Int -> Int -> ([Int], [Int], [Int]) split3Ways xs from to @@ -28,4 +31,22 @@ parseInput = (fmap read) . (splitOn ",") solve1 :: [Char] -> Int solve1 = solve1' . parseInput +sparseHash :: [Int] -> [Int] +sparseHash xs = let (ys, _, _) = foldl step ([0 .. 255], 0, 0) $ take (64 * (length xs)) (cycle xs) in ys + +stepHash :: (Int, [Int]) -> (Int, [Int]) +stepHash (xs, ys) = (foldl1 xor (take 16 ys), drop 16 ys) + +int2Hex :: Int -> [Char] +int2Hex xs + | length ys == 2 = ys + | otherwise = '0':ys + where ys = showHex xs "" + +denseHash :: [Int] -> [Char] +denseHash xs = mconcat $ fmap (int2Hex . fst) $ take 16 $ drop 1 $ iterate stepHash (0, xs) + +solve2 :: [Char] +solve2 = denseHash $ sparseHash $ (ord <$> input) ++ [17, 31, 73, 47, 23] + input = "120,93,0,90,5,80,129,74,1,165,204,255,254,2,50,113" |