组合数取余(Mod 可以不为质数)

using namespace std;

const int MAXN = 200005;

bool ispri[MAXN];
int prime[MAXN];
int priCnt;

void CalPrime()
{
    priCnt = 0;
    memset(ispri,false,sizeof(ispri));

    for(int i = 2;i < MAXN; ++i)
    {
        if(ispri[i] == false)
        {
            prime[priCnt++] = i;
            for(int j = i+i;j < MAXN; j += i)
                ispri[j] = true;
        }
    }
}

LL DivideByPrime(LL N,LL P)
{
    LL ans = 0;

    while(N)
        ans += N/P,N /= P;

    return ans;
}

LL QuickMod(LL a,LL b,LL m)
{
    LL ans = 1;
    a %= m;
    while(b)
    {
        if(b&1)
            ans = ans*a%m,b--;
        b >>= 1;
        a = a*a%m;
    }
    return ans;
}

//C(N,M) % P
LL CalCnmModP(LL N,LL M,LL P)
{
    LL ans = 1;
    for(int i = 0 ;i < priCnt && prime[i] <= N; ++i)
    {
        LL x = DivideByPrime(N,prime[i]);
        LL y = DivideByPrime(N-M,prime[i]);
        LL z = DivideByPrime(M,prime[i]);

        x -= (y+z);

        ans *= QuickMod(prime[i],x,P);
        ans %= P;
    }
    return ans;
}