素数筛选和合数分解

const int maxn=10000;
int prime[maxn+1];
void Prime(){
   clr(prime,0);
   for(int i=2;i<=maxn;i++){
        if(!prime[i])  prime[++prime[0]]=i;
        for(int j=1;j<=prime[0]&&prime[j]<=maxn/i;j++){
            prime[prime[j]*i]=1;
            if(i%prime[j]==0)  break;
       }
   }
}

int factor[100][2];
int fatcnt;
int getFactor(int x){

   fatcnt=0;
   int  tmp=x;
   for(int i=1;prime[i]<=tmp/prime[i];i++)
   {
       factor[fatcnt][1]=0;
       if(tmp%prime[i]==0){
           factor[fatcnt][0]=prime[i];
           while(tmp%prime[i]==0){
            factor[fatcnt][1]++;
            tmp/=prime[i];
           }
           fatcnt++;
       }
   }
   if(tmp!=1)
   {
       factor[fatcnt][0]=tmp;            //合数分解的因子存在 factor[][0] 里面
       factor[fatcnt++][1]=1;
   }
   return fatcnt;             
}