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Day 14, both parts done

This commit is contained in:
Jonathan Chan 2017-12-14 10:32:13 -08:00
parent ac2c786b6c
commit ade0446c62
1 changed files with 25 additions and 15 deletions
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14.hs
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@ -2,12 +2,15 @@ import Data.List.Split (chunksOf)
import Data.Char (ord) import Data.Char (ord)
import Data.Bits (xor) import Data.Bits (xor)
import Text.Printf (printf) import Text.Printf (printf)
import Data.Matrix (Matrix, fromLists, safeGet) import Data.Graph (graphFromEdges, scc)
import Data.HashSet (Set, member, insert) import Data.Sequence (Seq, index, fromList)
type Length = Int type Length = Int
type State = ([Int], Int, Int) type State = ([Int], Int, Int)
type Edge = (Int, Int, [Int])
(%) = mod (%) = mod
(//) = div
(!) = index
twist :: State -> Length -> State twist :: State -> Length -> State
twist (ring, position, skip) len = twist (ring, position, skip) len =
@ -25,19 +28,26 @@ sparseHash lengths =
let (hashed, _, _) = iterate (hash lengths) ([0..255], 0, 0) !! 64 let (hashed, _, _) = iterate (hash lengths) ([0..255], 0, 0) !! 64
in concat . map (printf "%08b" . foldr xor 0) . chunksOf 16 $ hashed in concat . map (printf "%08b" . foldr xor 0) . chunksOf 16 $ hashed
visit :: Matrix Int -> (Int, Int) -> Set (Int, Int) -> Set (Int, Int) getEdges :: Int -> (Seq Char, [Edge]) -> (Seq Char, [Edge])
visit matrix (row, col) seen = if member (row, col) seen then seen else getEdges ind (str, edges) = if str ! ind == '0' then (str, edges) else
let newSeen = insert (row, col) seen let row = ind // 128
in col = ind % 128
case safeGet row col matrix of neighbours = [(row + 1, col ),
Nothing -> seen (row - 1, col ),
Just 0 -> newSeen (row, col + 1),
Just 1 -> foldr (visit matrix) newSeen [(row + 1, col), (row - 1, col), (row, col + 1), (row, col - 1)] (row, col - 1)]
validNeighbours = filter isOne . map toIndex . filter inBounds $ neighbours
in (str, (ind, ind, validNeighbours) : edges)
where
inBounds (r, c) = r >= 0 && r <= 127 && c >= 0 && c <= 127
toIndex (r, c) = r * 128 + c
isOne i = (str ! i) == '1'
main :: IO () main :: IO ()
main = do main = do
let hashes = map (sparseHash . (++ [17, 31, 73, 47, 23]) . map ord . ("ffayrhll-" ++) . show) [0..127] let hashes = concat $ map (sparseHash . (++ [17, 31, 73, 47, 23]) . map ord . ("ffayrhll-" ++) . show) [0..127]
used = length . filter (== '1') . concat $ hashes used = length . filter (== '1') $ hashes
matrix = fromLists hashes (_, edges) = foldr getEdges (fromList hashes, []) [0..128 * 128 - 1]
(graph, _, _) = graphFromEdges edges
print $ used print $ used
mapM_ print hashes print $ length . scc $ graph