AC代码：

#include 
     
      #include 
      
       #include 
       
        using namespace std;#define maxn 100005int a[maxn],judge[maxn];int main(void){    freopen("in.txt","r",stdin);    memset(judge,0,sizeof(judge));    long long n;    int j=0;        scanf("%lld",&n);        for(int i=2;i<=n;i++)    {        if(judge[i]==0)            a[j++]=i;        for(int k=i;k<=n;k+=i)            judge[k]=1;    }        for(int i=0;i