【bzoj2982】 combination LUCAS定理

#include<cstdio>
#include<cstring>
#include<cstdlib>
#include<cmath>
#include<iostream>
#include<algorithm>
#define mod 10007

using namespace std;

int fac[100010],inv[100010];
int n,m,T;

int power(long long x,int k)
{
	long long ans=1;
	while (k)
	{
		if (k&1) ans=ans*x%mod;
		x=x*x%mod;
		k>>=1;
	}
	return ans;
}

int C(int x,int y)
{
	if (x<y) return 0;
	if (x<mod && y<mod) return (long long)(fac[x]*inv[y]%mod)*inv[x-y]%mod;
	return (long long)C(x%mod,y%mod)*C(x/mod,y/mod)%mod;
}

int main()
{
	scanf("%d",&T);
	fac[0]=1;
	for (int i=1;i<10007;i++) fac[i]=(long long)fac[i-1]*i%mod;
	inv[10006]=power(fac[10006],mod-2);
	for (int i=10005;i>=0;i--) inv[i]=(inv[i+1]*(i+1))%mod;
	while (T--)
	{
		scanf("%d%d",&n,&m);
		printf("%d\n",C(n,m));
	}
	return 0;
}