X-Git-Url: https://git.njae.me.uk/?a=blobdiff_plain;f=src%2Fadvent14%2Fadvent14.hs;h=698853c7bcd2c60b0a891598e0ee9b0bbcc9f41f;hb=fc23edeb0e66a61d640dfeaffd5a274a63acf8c8;hp=940fe7b4d9c6ed811589001b66ff34b075eb1821;hpb=0c672ee4c5d50a7e51b0408ae1b87f68c44534a7;p=advent-of-code-17.git

diff --git a/src/advent14/advent14.hs b/src/advent14/advent14.hs
index 940fe7b..698853c 100644
--- a/src/advent14/advent14.hs
+++ b/src/advent14/advent14.hs
@@ -2,22 +2,59 @@ import Data.List.Split (chunksOf)
 import Data.Char (ord)
 import Text.Printf (printf)
 import Data.Bits (xor)
+import qualified Data.Set as S
+import qualified Data.Graph as G
+import Control.Parallel.Strategies (parMap, rpar)
+
+type CellSet = S.Set (Int, Int)
 
 puzzleKey = "xlqgujun"
 
+main :: IO ()
+main = do
+  print $ part1 puzzleKey
+  print $ part2 puzzleKey
+
 
 part1 :: String -> Int
 part1 key = sum rowCounts
-    where hashes = map knotHash $ rowSpecs key
-          rowCounts = map (countSetBits . binify) hashes
+    where rowCounts = parMap rpar countSetBits $ binHashes key
+
+
+part2 :: String -> Int
+part2 key = length $ cellEdges cells
+    where cells = presentCells $ binHashes key
+
+binHashes :: String -> [String]
+binHashes key = parMap rpar binHash $ rowSpecs key
+
+
+binHash :: String -> String
+binHash = binify . knotHash
+
+numKey :: (Int, Int) -> Int
+numKey (r, c) = 128 * r + c
+
+
+presentCells :: [String] -> CellSet
+presentCells bhs = S.fromList [(r, c) | r <- [0..127], c <- [0..127], (bhs!!r)!!c == '1']
+
+adjacentCells :: CellSet -> (Int, Int) -> [(Int, Int)]
+adjacentCells cells (r, c) = filter (\k -> S.member k cells) possibles
+  where possibles = [(r, c - 1), (r, c + 1), (r - 1, c), (r + 1, c)]
+
+
+cellEdges :: CellSet -> [G.SCC (Int, Int)]
+cellEdges cells = G.stronglyConnComp [(k, numKey k, map numKey $ adjacentCells cells k) | k <- S.elems cells]
 
 rowSpecs :: String -> [String]
-rowSpecs key = map (((key ++ "-") ++) . show) [0..127]
+rowSpecs key = map (((key ++ "-") ++) . show) ([0..127] :: [Integer])
 
 countSetBits :: String -> Int
 countSetBits = length . filter (== '1')
 
 
+
 knotHash :: String -> [Int]
 knotHash input = densify tied
     where (tied, _, _) = foldl step ([0..255], 0, 0) hashTerms
@@ -47,8 +84,8 @@ mkHashTerms :: String -> [Int]
 mkHashTerms text = take (length chunk * 64) $ cycle chunk
     where chunk = map ord text ++ [17, 31, 73, 47, 23]
 
-hexify :: [Int] -> String
-hexify = concatMap (printf "%02x")
+-- hexify :: [Int] -> String
+-- hexify = concatMap (printf "%02x")
 
 binify :: [Int] -> String
 binify = concatMap (printf "%08b")
@@ -57,4 +94,4 @@ densify :: [Int] -> [Int]
 densify ns = codes
     where chunks = chunksOf 16 ns
           compress = foldl1 xor
-          codes = map compress chunks
\ No newline at end of file
+          codes = map compress chunks