求组合数m_n

下面为求取组合数的代码：

#include <stdio.h>
#define MAX 10009
int prime[168];
void print(int *v, int length)
{
    int i = 0;
    for (; i < length; i++)
        printf("%d ", v[i]);
    putchar('\n');
}

int getPrime()
{
    int i = 3, k = 1;
    int j = 0;
    int flag;
    prime[0] = 2;
    for (; i < 1000; i++) {
        for (flag = 0, j = 0; j < k; j++) {
            if (i % prime[j] == 0) {
                flag = 1;
                break;
            }
        }
        if (!flag)
            prime[k++] = i;
    }
    print(prime, 168);
}

int comb(int m, int n)
{
    int count[168] = { 0 };
    int i = 0, j = 0;
    int mm;
    int mul = 1, tmp;
    for (i = m; i > m - n; i--) {
        mm = i;
        for (j = 0; mm != 1; j++) {
            if (mm % prime[j] == 0) {
                mm /= prime[j];
                ++count[j];
                --j;
            }
        }
    }
    for (i = n; i >= 2; i--) {
        mm = i;
        for (j = 0; mm != 1; j++)
            if (mm % prime[j] == 0) {
                mm /= prime[j];
                --count[j];
                --j;
            }
    }
    for (i = 0; i < 168; i++) {
        tmp = count[i];
        while (tmp) {
            mul = (mul * prime[i]) % MAX;
            tmp--;
        }
    }
    return mul;
}

int main()
{
    getPrime();
    printf("%d\n", comb(2, 1));
    return 0;
}