NC16596 [NOIP2011]计算系数

https://ac.nowcoder.com/acm/problem/16596

点击查看代码

#include <bits/stdc++.h>
using namespace std;

#define int long long

int mod = 10007;
int frac[1002];

void ini()
{
    frac[0] = frac[1] = 1;
    for(int i=2;i<=1001;++i)
        frac[i] = frac[i-1] * i % mod;
}

int pf(int x,int b)
{
    int res = 1;
    while(b>0)
    {
        if(b&1) res = res * x % mod;
        x = x * x % mod;
        b >>= 1;
    }
    return res;
}

int C(int n,int k)
{
    return frac[n] * pf(frac[k], mod-2) % mod * pf(frac[n-k], mod-2) % mod;
}

signed main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);cout.tie(0);

    int a,b,n,m,k;
    cin >> a >> b >> k >> n >> m;
    ini();
    //cout << C(k, m)  << " " << pf(a, n) << " " << pf(b, m) << endl;
    cout << C(k, m) * pf(a, n) % mod * pf(b, m) % mod << endl;


    return 0;
}