38 lines
1.4 KiB
Haskell
38 lines
1.4 KiB
Haskell
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import Aoc
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import Data.List.Split ( splitOn )
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parseFile :: [String] -> [(String, (Int, Int), (Int, Int))]
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parseFile = map (\line ->
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let line' = words line in
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let (command, [pos1, "through", pos2]) = splitAt (length line' - 3) line' in
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(unwords command, pos pos1, pos pos2))
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where pos = pair . map read . splitOn ","
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doCommands :: (a -> String -> a) -> a -> [(String, (Int, Int), (Int, Int))] -> (Int, Int) -> a
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doCommands doCommand start commands pos = foldl (doCommand' pos) start commands
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where
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within (x0, y0) (x1, y1) (x, y) = x0 <= x && x <= x1 && y0 <= y && y <= y1
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doCommand' pos state (command, pos1, pos2) = if within pos1 pos2 pos then doCommand state command else state
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part1 :: [(String, (Int, Int), (Int, Int))] -> Int
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part1 commands = length $ filter isOn [(x, y) | x <- [0..999], y <- [0..999]]
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where
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doCommand state "turn off" = False
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doCommand state "turn on" = True
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doCommand state "toggle" = not state
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isOn = doCommands doCommand False commands
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part2 :: [(String, (Int, Int), (Int, Int))] -> Int
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part2 commands = sum [brightness (x, y) | x <- [0 .. 999], y <- [0 .. 999]]
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where
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doCommand state "turn off" = max 0 (state - 1)
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doCommand state "turn on" = state + 1
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doCommand state "toggle" = state + 2
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brightness = doCommands doCommand 0 commands
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main :: IO ()
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main = aocMain parseFile part1 part2
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