Done part 2

[advent-of-code-20.git] / advent17 / src / advent17.hs

diff --git a/advent17/src/advent17.hs b/advent17/src/advent17.hs
index 535f971ab508216a7938512310788a53a660bc4b..27b10f4008b3e3d946d18f0f8da871a374f2ba35 100644 (file)
--- a/advent17/src/advent17.hs
+++ b/advent17/src/advent17.hs
@@ -1,51 +1,81 @@
 -- import Debug.Trace
 
 import qualified Data.Set as S
-import Linear (V3(..), V4(..), (^+^), (^-^))
-import qualified Data.Vector as V
+import Linear (V3(..), V4(..), (^+^))
 
-type Coord = V3 Int -- x, y, z
-type Grid = S.Set Coord
+class (Num a, Ord a) => Coord a where
+    (^+^^) :: a -> a -> a
+    neighbourCells :: S.Set a
+instance Coord (V3 Int) where
+    x ^+^^ y  = x ^+^ y
+    neighbourCells = S.fromList [ V3 dx dy dz
+             | dx <- [-1, 0, 1]
+             , dy <- [-1, 0, 1]
+             , dz <- [-1, 0, 1]
+             , (dx, dy, dz) /= (0, 0, 0)
+             ]
+instance Coord (V4 Int) where
+    x ^+^^ y  = x ^+^ y
+    neighbourCells = S.fromList [ V4 dx dy dz dw
+             | dx <- [-1, 0, 1]
+             , dy <- [-1, 0, 1]
+             , dz <- [-1, 0, 1]
+             , dw <- [-1, 0, 1]
+             , (dx, dy, dz, dw) /= (0, 0, 0, 0)
+             ]
+
+type Grid a = S.Set a
 
 main :: IO ()
 main = 
     do grid0 <- readGrid "data/advent17.txt"
-       print grid0
-       let finalGrid = head $ drop 6 $ iterate update grid0
-       print $ S.size finalGrid
+       print $ part1 grid0
+       print $ part2 grid0
+
 
+part1 grid0 = S.size finalGrid
+  where finalGrid = head $ drop 6 $ iterate update grid0
 
-readGrid :: String -> IO Grid
+part2 grid0 = S.size finalGrid
+  where grid4 = conv34 grid0
+        finalGrid = head $ drop 6 $ iterate update grid4
+
+
+readGrid :: String -> IO (Grid (V3 Int))
 readGrid filename = 
     do  gs <- readFile filename
         let grid = lines gs
         let isActive x y = (grid!!y)!!x == '#'
         let maxX = length (head grid) - 1
         let maxY = length grid - 1
-        return $ S.fromList [ V3 x y 0 | x <- [0..maxX], y <- [0..maxY], isActive x y]
+        return $ S.fromList [ V3 x y 0 
+                            | x <- [0..maxX], y <- [0..maxY], isActive x y]
 
-neighbourSpaces :: Coord -> Grid
-neighbourSpaces here = S.map (here ^+^) nbrs
-  where nbrs = S.fromList [ V3 dx dy dz
-             | dx <- [-1, 0, 1]
-             , dy <- [-1, 0, 1]
-             , dz <- [-1, 0, 1]
-             , (dx, dy, dz) /= (0, 0, 0)]
+conv34 :: Grid (V3 Int) -> Grid (V4 Int)
+conv34 grid = S.map conv34Cell grid
+
+conv34Cell (V3 x y z) = V4 x y z 0
+
+
+neighbourSpaces :: Coord a => a -> Grid a
+neighbourSpaces here = S.map (here ^+^^) neighbourCells
 
-countOccupiedNeighbours :: Coord -> Grid -> Int
-countOccupiedNeighbours cell grid = S.size $ S.intersection grid $ neighbourSpaces cell
+countOccupiedNeighbours :: Coord a => a -> Grid a -> Int
+countOccupiedNeighbours cell grid = 
+    S.size $ S.intersection grid $ neighbourSpaces cell
 
-cubeSurvives :: Grid -> Coord -> Bool
+cubeSurvives :: Coord a => Grid a -> a -> Bool
 cubeSurvives grid cell = alive && (nNbrs == 2 || nNbrs == 3)
   where alive = cell `S.member` grid
         nNbrs = countOccupiedNeighbours cell grid
 
-cubeBorn :: Grid -> Coord -> Bool
+cubeBorn :: Coord a => Grid a -> a -> Bool
 cubeBorn grid cell = dead && (nNbrs == 3)
   where dead = cell `S.notMember` grid
         nNbrs = countOccupiedNeighbours cell grid
 
-update :: Grid -> Grid
-update grid = S.union (S.filter (cubeSurvives grid) grid) (S.filter (cubeBorn grid) empties)
+update :: Coord a => Grid a -> Grid a
+update grid = S.union (S.filter (cubeSurvives grid) grid) 
+                      (S.filter (cubeBorn grid) empties)
   where empties = (S.foldr mergeEmpties S.empty grid) `S.difference` grid
         mergeEmpties cell acc = S.union acc $ neighbourSpaces cell