矮人砍树 组合数取余 排列数质因数个数 快速幂

#include<stdio.h>
#include<cmath>
#include<string.h>
__int64 p[95]={2,3,5,7,11,13,17,19,23,29,31,37,41,43,47,53,59,61,67,71,73,79,83,89,97,101,103,
107,109,113,127,131,137,139,149,151,157,163,167,173,179,181,191,193,197,199,211,
223,227,229,233,239,241,251,257,263,269,271,277,281,283,293,307,311,313,317,331,
337,347,349,353,359,367,373,379,383,389,397,401,409,419,421,431,433,439,443,449,
457,461,463,467,479,487,491,499};
int main()
{
__int64 n,m,i,j,a[95],b[95],tmp,res,tmpn,tmpm;
    while(scanf("%I64d%I64d",&n,&m)!=EOF)
    {
        if(n%2==0&&m>n/2||n%2!=0&&m>n/2+1) {printf("0\n");continue;}
        n=n-m+1;
        tmpn=n;tmpm=m;
        memset(a,0,sizeof a);memset(b,0,sizeof b);
        for(i=0;i<95;i++)
        {
            n=tmpn;m=tmpm;tmp=tmpn-tmpm;
            while(n/p[i])  {a[i]+=n/p[i];n/=p[i];}
            while(m/p[i])  {a[i]-=m/p[i];m/=p[i];}
            while(tmp/p[i])  {a[i]-= tmp/p[i] ;tmp/=p[i];}
        }
        res=1;
        for(i=0;i<95;i++)
        {
            tmp=p[i];
            while(a[i]>0)
            {
                if(a[i]&1) 
                {
                    res*=tmp;
                    res%=10007;
                }
                a[i]>>=1;
                tmp*=p[i];tmp%=10007;
            }
        }

        printf("%I64d\n",res);
    }
    return 0;
}