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| 1 | +-- https://github.com/minoki/my-atcoder-solutions |
| 2 | +{-# LANGUAGE TypeApplications #-} |
| 3 | +{-# LANGUAGE BangPatterns #-} |
| 4 | +import Data.Int (Int64) |
| 5 | +import qualified Data.ByteString.Char8 as BS |
| 6 | +import Data.Ratio |
| 7 | + |
| 8 | +main = do |
| 9 | + [cx,cy,r] <- map (read @Double . BS.unpack) . BS.words <$> BS.getLine |
| 10 | + let cx4, cy4, r4 :: Int64 |
| 11 | + cx4 = round (cx * 10^4) |
| 12 | + cy4 = round (cy * 10^4) |
| 13 | + r4 = round (r * 10^4) |
| 14 | + isInside x y = (10^4 * x - cx4)^2 + (10^4 * y - cy4)^2 <= r4^2 |
| 15 | + minX = ceiling $ (cx4 - r4) % (10^4) |
| 16 | + maxX = floor $ (cx4 + r4) % (10^4) |
| 17 | + go1 !acc !x !yB !yT | x > maxX = acc |
| 18 | + | otherwise = let yB' = if isInside x yB then |
| 19 | + let go !y | isInside x (y - 1) = go (y - 1) |
| 20 | + | otherwise = y |
| 21 | + in go yB |
| 22 | + else |
| 23 | + let go !y | isInside x (y + 1) = y + 1 |
| 24 | + | y > yT = y |
| 25 | + | otherwise = go (y + 1) |
| 26 | + in go yB |
| 27 | + yT' = if isInside x yT then |
| 28 | + let go !y | isInside x (y + 1) = go (y + 1) |
| 29 | + | otherwise = y |
| 30 | + in go yT |
| 31 | + else |
| 32 | + let go !y | isInside x (y - 1) = y - 1 |
| 33 | + | y < yB = y |
| 34 | + | otherwise = go (y - 1) |
| 35 | + in go yT |
| 36 | + in if yT' < yB' then |
| 37 | + acc |
| 38 | + else |
| 39 | + go1 (acc + yT' - yB' + 1) (x + 1) yB' yT' |
| 40 | + y0 = round cy |
| 41 | + go0 !x | x > maxX = 0 |
| 42 | + | otherwise = if isInside x y0 then |
| 43 | + go1 0 x y0 y0 |
| 44 | + else |
| 45 | + go0 (x + 1) |
| 46 | + print $ go0 minX |
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