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Re:过了贴代码攒rp,有注释有真相

Posted by 504512803 at 2012-02-04 15:45:39 on Problem 2739
In Reply To:过了贴代码攒rp,有注释有真相 Posted by:1000010314 at 2012-01-21 14:11:38
> #include <iostream>
> #include <cstdlib>
> #include <cstdio>
> #include <cstring>
> #define max 10001
> #define sum 1230//10000以下总共有1229个素数
> using namespace std;
> int prime [sum];//这个数组用于存放素数
> 
> int num(int n)//用于计算可能的组合的个数。
> {
>     int a=prime[1],ans=0;//ans为个数,a为当前计算的和,n为目标值
>     for(int i=1,j=2;j<sum&&prime[i]<=n&&i<=j;i++)
>     {
>         a-=prime[i-1];
>         while(a<n&&j<sum)
>         {
>             a+=prime[j++];
>         }
>         if(a==n){ans++;}
>     }
>     return ans;
> }
> 
> 
> int main()
> {
>     bool * data=new bool [max];//双下标法找素数
>     memset(data,true,max*sizeof(bool));
>     data[0]=false;data[1]=false;prime[0]=0;
>     for(int i=2,j=1,k;i<max;i++)
>     {
>         if(!data[i]){continue;}
>         prime[j++]=i;//记录素数
>         for(k=(i<<1);k<max;k+=i){data[k]=false;}
>     }
>     delete(data);//不用了就释放内存
>     int n;
>     while(cin>>n)
>     {
>         if(!n){break;}
>         cout<<num(n)<<endl;
>     }
>     return 0;
> }

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