Day 15

[advent-of-code-17.git] / src / advent14 / advent14.hs

diff --git a/src/advent14/advent14.hs b/src/advent14/advent14.hs
index 5ca281766e91e03b4f8d75644b8504f7bbf43ccc..698853c7bcd2c60b0a891598e0ee9b0bbcc9f41f 100644 (file)
--- a/src/advent14/advent14.hs
+++ b/src/advent14/advent14.hs
@@ -2,10 +2,11 @@ import Data.List.Split (chunksOf)
 import Data.Char (ord)
 import Text.Printf (printf)
 import Data.Bits (xor)
-import qualified Data.Map.Strict as M
+import qualified Data.Set as S
 import qualified Data.Graph as G
+import Control.Parallel.Strategies (parMap, rpar)
 
-type CellMap = M.Map (Int, Int) Bool
+type CellSet = S.Set (Int, Int)
 
 puzzleKey = "xlqgujun"
 
@@ -17,14 +18,16 @@ main = do
 
 part1 :: String -> Int
 part1 key = sum rowCounts
-    where binHashes = map binHash $ rowSpecs key
-          rowCounts = map countSetBits binHashes
+    where rowCounts = parMap rpar countSetBits $ binHashes key
 
 
 part2 :: String -> Int
 part2 key = length $ cellEdges cells
-    where binHashes = map binHash $ rowSpecs key
-          cells = presentCells binHashes
+    where cells = presentCells $ binHashes key
+
+binHashes :: String -> [String]
+binHashes key = parMap rpar binHash $ rowSpecs key
+
 
 binHash :: String -> String
 binHash = binify . knotHash
@@ -33,16 +36,16 @@ numKey :: (Int, Int) -> Int
 numKey (r, c) = 128 * r + c
 
 
-presentCells :: [String] -> CellMap
-presentCells binHashes = M.fromList [((r, c), True) | r <- [0..127], c <- [0..127], (binHashes!!r)!!c == '1']
+presentCells :: [String] -> CellSet
+presentCells bhs = S.fromList [(r, c) | r <- [0..127], c <- [0..127], (bhs!!r)!!c == '1']
 
-adjacentCells :: CellMap -> (Int, Int) -> [(Int, Int)]
-adjacentCells cells (r, c) = filter (\k -> M.member k cells) possibles
+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 :: CellMap -> [G.SCC (Int, Int)]
-cellEdges cells = G.stronglyConnComp [(k, numKey k, map numKey $ adjacentCells cells k) | k <- M.keys cells]
+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] :: [Integer])