题解 | #牛牛的排列数#

给大家展示一个笨方法

#include <stdio.h>

int main() 
{
    long n, m;
    scanf("%ld %ld", &n, &m);
    
    long up = 1;
    long down = 1;
    if(n > m)
    {
        m = n - m;
        
        for(up = 1; n > 1; n--)
        {
            up *= n;
        }
        for(down = 1; m > 1; m--)
        {
            down *= m;
        }
    }
    else 
    {
        up = 0;
    }
    printf("%ld", up / down);
    
    return 0;
}