177. [USACO Jan07] 有限制的素数

 1 #include<iostream>
 2 #include<cstdio>
 3 #include<cmath>
 4 using namespace std;
 5 int a,b,n;
 6 int flag=0;
 7 int tot=0;
 8 int vis[10000001];
 9 int main()
10 {
11     freopen("qprime.in","r",stdin);
12     freopen("qprime.out","w",stdout);
13     cin>>a>>b>>n;
14     for(int i=2;i<=sqrt(b+0.5);i++)
15     {
16         if(!vis[i])
17         for(int j=i*i;j<=b;j=j+i)
18         {
19             vis[j]=1;
20         }
21     }
22     for(int i=a;i<=b;i++)
23     {
24         if(vis[i]==0)
25         {
26             flag=0;
27             int d=i;
28              
29             while(d!=0)
30             {
31                 int gw=d%10;
32                 if(gw==n)
33                 {
34                     flag=1;
35                     break;
36                 }
37                 else 
38                 {
39                     d=d/10;
40                 }
41             }
42             if(flag==1)
43             tot++;
44         }
45         else continue;
46         
47     }
48     cout<<tot;
49     fclose(stdin);
50     fclose(stdout);
51     return 0;
52 }