Submission #122653

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Source Code Expand

import Control.Monad
import Control.Applicative
import Data.List
import Text.Printf

main :: IO ()
main = do
  [r, c] <- map read . words <$> getLine
  [x, y] <- map read . words <$> getLine
  [d, l] <- map read . words <$> getLine
  print $ (solve x y d l * (r-x+1) * (c-y+1) `mod` 1000000007 :: Integer)

solve 1 1 _ _ = 1
solve x y d l = sum $ do
  dx1 <- [0, 1]
  dx2 <- [0, 1]
  dy1 <- [0, 1]
  dy2 <- [0, 1]
  return $
    (-1)^(dx1+dx2+dy1+dy2) *
    comb ((x-dx1-dx2)*(y-dy1-dy2)) d *
    comb ((x-dx1-dx2)*(y-dy1-dy2)-d) l

comb a b | a < b = 0
comb _ b | b < 0 = 0
comb _ 0 = 1
comb a b = comb (a-1) (b-1) * a `div` b

Submission Info

Judge Result