HDU2161

解题思路：判断素数模板题。

#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;
const int maxn = 16005;
int vis[maxn];

void Init()
{
    memset(vis, 0, sizeof(vis));
    vis[1] = 1;
    for(int i = 2; i <= maxn; i++)
    {
        for(int j = i+i; j <= maxn; j +=i)
            vis[j] = 1;
    }
    return ;
}
int main()
{
    Init();
    int n, kase = 1;
    while(~scanf("%d", &n))
    {
        if(n <= 0) break;
        if(n == 1 || n == 2)
        {
            printf("%d: no
", kase++);
            continue;
        }
        if(!vis[n]) printf("%d: yes
", kase++);
        else printf("%d: no
", kase++);
    }
    return 0;
}