public BinomialCoefficient(int n)
{
fact = new ModInt[n + 1];
ifact = new ModInt[n + 1];
fact[0] = 1;
for (int i = 1; i <= n; i++)
{
fact[i] = fact[i - 1] * i;
}
ifact[n] = ModInt.Inverse(fact[n]);
for (int i = n - 1; i >= 0; i--)
{
ifact[i] = ifact[i + 1] * (i + 1);
}
ifact[0] = ifact[1];
}
public static ModInt Pow(ModInt value, long k)
{
return(Pow(value.value_, k));
}
public static ModInt Inverse(ModInt value)
{
return(Pow(value, P - 2));
}