31 lines
1.6 KiB
Haskell
31 lines
1.6 KiB
Haskell
module Part1 where
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import Commons
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import Data.Array (Ix(inRange), bounds, (!))
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import Data.Maybe (catMaybes)
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cleanAstarNext :: City -> [Node] -> [(Node, Int)]
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cleanAstarNext city = map (\ (c, d, n) -> ((c, d, n), city ! c))
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. filter (\ ((y, x), _, n) -> inRange (bounds city) (y, x) && n <= 3)
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astarNext :: City -> Node -> [(Node, Int)]
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astarNext city ((y, x), East, n) = cleanAstarNext city [((y - 1, x), North, 1),
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((y + 1, x), South, 1),
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((y, x + 1), East, n + 1)]
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astarNext city ((y, x), South, n) = cleanAstarNext city [((y + 1, x), South, n + 1),
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((y, x + 1), East, 1),
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((y, x - 1), West, 1)]
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astarNext city ((y, x), West, n) = cleanAstarNext city [((y - 1, x), North, 1),
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((y + 1, x), South, 1),
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((y, x - 1), West, n + 1)]
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astarNext city ((y, x), North, n) = cleanAstarNext city [((y - 1, x), North, n + 1),
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((y, x + 1), East, 1),
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((y, x - 1), West, 1)]
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applyAstar :: City -> Direction -> Int -> Maybe Int
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applyAstar city d n = astar ((1, 1), East, 0) (snd $ bounds city, d, n) (astarNext city) astarEstimation
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getAllAstar :: City -> [Int]
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getAllAstar city = catMaybes [applyAstar city d n | d <- [East, South], n <- [1..3]]
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