Lucas求大数组合数模板

void init()
{
    int i;
    fac[0] =1;
    for(i =1; i <= p; i++)
        fac[i] = fac[i-1]*i % p;
}

llg pow(llg a, llg b)
{
    llg tmp = a % p, ans =1;
    while(b)
    {
        if(b &1)  ans = ans * tmp % p;
        tmp = tmp*tmp % p;
        b >>=1;
    }
    return  ans;
}

llg C(llg n, llg m)
{
    if(m > n)  return0;
    return  fac[n]*pow(fac[m]*fac[n-m], p-2) % p;
}

llg Lucas(llg n, llg m)
{
    if(m ==0)  return1;
    elsereturn  (C(n%p, m%p)*Lucas(n/p, m/p))%p;
}

void init() {
    p[0] = p[1] = I[0] = I[1] = 1;
    for (int i = 2 ; i < N ; ++ i)
        I[i] = (Q - Q / i) * I[Q % i] % Q;
    for (int i = 2 ; i < N ; ++ i) {
        p[i] = p[i - 1] * i % Q;
        I[i] = I[i - 1] * I[i] % Q;
    }
}
LL C(int x , int y) {
    return p[x] * I[y] % Q * I[x - y] % Q;
}