Submission #40666842

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Source Code Expand

{-# LANGUAGE MultiWayIf #-}
import Data.Array.IArray
import Data.Maybe
import Data.Ratio
import qualified Data.ByteString.Char8 as C

main :: IO ()
main = do
    [n, a, b, p, q] <- getInts
    let dp = fArray ((1,1), (n,n)) f :: Array (Int, Int) MInt
        pqinv = 1 / (fromIntegral p * fromIntegral q)
        f (i,j) = sum os * pqinv where
            os = do
                ra <- [1..p]
                rb <- [1..q]
                let i' = min n (i + ra)
                    j' = min n (j + rb)
                if | i' == n   -> pure 1
                   | j' == n   -> pure 0
                   | otherwise -> pure $ dp!(i',j')
    print $ unMInt $ dp!(a,b)

getInts :: IO [Int]
getInts = map (fst . fromJust . C.readInt) . C.words <$> C.getLine

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mm :: Int
mm = 998244353

newtype MInt = MInt { unMInt :: Int } deriving (Eq, Ord, Show)

instance Num MInt where
    MInt a + MInt b = MInt $ let c = a + b in if c >= mm then c - mm else c
    MInt a - MInt b = MInt $ let c = a - b in if c < 0 then c + mm else c
    MInt a * MInt b = MInt $ a * b `mod` mm
    abs             = id
    signum          = MInt . signum . unMInt
    fromInteger     = MInt . fromInteger . (`mod` fromIntegral mm)

instance Fractional MInt where
    recip          = (^(mm - 2))
    fromRational r = fromIntegral (numerator r) / fromIntegral (denominator r)

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fArray :: (IArray a e, Ix i) => (i, i) -> (i -> e) -> a i e
fArray b f = listArray b (f <$> range b)
{-# INLINE fArray #-}

Submission Info

Compile Error

Loaded package environment from /home/contestant/.ghc/x86_64-linux-8.8.3/environments/default

Judge Result