一本通1648：【例 1】「NOIP2011」计算系数

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于 2024-05-18 17:11:03 发布

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文章标签：算法 c++

本文链接：https://blog.youkuaiyun.com/liu12345635/article/details/139028427

版权

#include <cstdio>
#define LL long long

const int mod = 10007;
LL f[1010];

LL qmi(LL a, int b) {
    LL res = 1;

    while (b) {
        if (b & 1)
            res = res * a % mod;

        a = a * a % mod;
        b >>= 1;
    }

    return res;
}

int main() {
    int a, b, k, n, m;
    scanf("%d %d %d %d %d", &a, &b, &k, &n, &m);
    f[0] = 1;

    for (int i = 1; i <= k; i ++)
        f[i] = f[i - 1] * i % mod;

    LL ans = f[k] * qmi(f[k - n], mod - 2) % mod * qmi(f[n], mod - 2) % mod * qmi(a, n) % mod * qmi(b, m) % mod;
    printf("%lld", ans);
    return 0;
}