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1 | 1 | module AOC2017.Day25 (day25a, day25b) where |
2 | 2 |
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3 | | -import AOC2017.Types (Challenge) |
| 3 | +import AOC2017.Types (Challenge) |
| 4 | +import AOC2017.Util |
| 5 | +import AOC2017.Util.Tape |
| 6 | +import Control.Lens |
| 7 | +import Control.Monad.Trans.Maybe |
| 8 | +import Control.Monad.Trans.State |
| 9 | +import Control.Monad.Trans.Writer |
| 10 | +import Data.Foldable |
| 11 | +import qualified Data.IntMap as IM |
| 12 | +import qualified Data.IntSet as IS |
| 13 | +import qualified Data.Map as M |
| 14 | +import qualified Data.Set as S |
| 15 | +import qualified Text.Megaparsec as P |
| 16 | +import qualified Text.Megaparsec.Char as P |
| 17 | + |
| 18 | +data St = SA | SB | SC | SD | SE | SF |
| 19 | + |
| 20 | +data Dir = DL | DR |
| 21 | + |
| 22 | +type Rule = (Bool, Dir, St) |
| 23 | + |
| 24 | +type TapeState = (Tape Bool, St) |
| 25 | + |
| 26 | + |
| 27 | +rule :: St -> (Rule, Rule) |
| 28 | +rule = \case |
| 29 | + SA -> ((True, DR, SB), (False, DR, SF)) |
| 30 | + SB -> ((False,DL, SB), (True, DL, SC)) |
| 31 | + SC -> ((True,DL,SD),(False, DR, SC)) |
| 32 | + SD -> ((True, DL, SE),(True, DR, SA)) |
| 33 | + SE -> ((True, DL, SF), (False, DL, SD)) |
| 34 | + SF -> ((True, DR, SA), (False, DL, SE)) |
| 35 | + |
| 36 | +step :: TapeState -> TapeState |
| 37 | +step (!t0, !st0) = (t1, st1) |
| 38 | + where |
| 39 | + t1 = t0 & tFocus .~ newFoc |
| 40 | + & case dirTurn of |
| 41 | + DL -> moveLeftD False |
| 42 | + DR -> moveRightD False |
| 43 | + (newFoc, dirTurn, st1) |
| 44 | + | t0 ^. tFocus = snd (rule st0) |
| 45 | + | otherwise = fst (rule st0) |
4 | 46 |
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5 | 47 | day25a :: Challenge |
6 | | -day25a = undefined |
| 48 | +day25a _ = show . length . filter id . toList . fst |
| 49 | + $ iterate step (Tape [] False [], SA ) !!! 12964419 |
7 | 50 |
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8 | 51 | day25b :: Challenge |
9 | 52 | day25b = undefined |
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