深搜超时。。。

#include <cstdio>
#include <cstdlib>
#include <iostream>
using namespace std;
int n,a[10];
int p[5]={0,2,3,5,7},q[6]={0,1,3,5,7,9};
int judge(int s)
{
    for (int k=2;k<=s-1;k++)
    {
        if (s%k==0)
        {
            return 0;
        }
    }
    return 1;
}
void dfs (int x,int step)
{
    int ss,j;
    if (judge(x)==0) return; 
    if (step==n) 
    {
        printf ("%d\n",x);
        return;
    }
    for (j=1;j<=5;j++)
    {
        dfs(x*10+q[j],step+1);
    }
}
int i;
int main ()
{
    //freopen ("Superprime Rib.in","r",stdin);
    scanf ("%d",&n);
    for (i=1;i<=4;i++)
    {
        dfs(p[i],1);
    }
    return 0;
}