Submission #134787

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Source Code Expand

MOD = 1e9.to_i+7
NUM = 1000
$combi = Array.new(NUM){Array.new(NUM,0)}
$combi[0][0] = 1
(NUM-1).times{|i|
  $combi[i][0] = $combi[i][i] = 1
  i.times{|j|
    $combi[i+1][j+1] = ($combi[i][j] + $combi[i][j+1]) % MOD
  }
}
R,C,X,Y,$D,$L = $<.map{|x|x.split}.flatten.map(&:to_i)

def f(x,y)
  # x*y choose D * x*y-D choose L
  return 0 if x<0 || y<0
  return 0 if $D+$L > x*y
  $combi[x*y][$D] * $combi[x*y-$D][$L] % MOD
end

ans = f(X,Y)
ans = ans*(R-X+1)*(C-Y+1)%MOD
ans = 0
(1 << 4).times{|s|
  next if s==0
  popcnt = 0
  x = X
  y = Y
  4.times{|i|
    if s>>i&1!=0
      i<2 ? x-=1 : y-=1
      popcnt += 1
    end
  }
  if popcnt.even?
    ans = (ans - f(x,y) + MOD) % MOD
  else
    ans = (ans + f(x,y)) % MOD
  end
}
ans = (f(X,Y) - ans + MOD) % MOD
ans = ans*(R-X+1)*(C-Y+1)%MOD

p ans

Submission Info

Judge Result