[](https://www.luogu.org/recordnew/show/17097859)
by YueYang1235 @ 2019-03-10 19:50:15
为什么链接插不上？
https://www.luogu.org/recordnew/show/17097859
by YueYang1235 @ 2019-03-10 19:50:55
好吧，只要粘贴一下
by YueYang1235 @ 2019-03-10 19:56:27
@[岳杨](/space/show?uid=151924) 一个一个写效率低爆。。。要用素数筛啊。。。看题解。。。
by 樱初音斗橡皮 @ 2019-03-10 20:10:29
埃拉托斯特尼?
```cpp
void prime()
{
bool f[n];
memset(f,true,sizeof(f));
f[0]=f[1]=false;
for(i=2;i<=sqrt(n);i++)
if(f[i])
for(j=i*i;j<=n;j+=i)
f[j]=false;
for(i=2;i<n;i++)
if(f[i])a[++len]=i;
}
```
by YueYang1235 @ 2019-03-10 21:03:44
@樱初音斗橡皮?
by YueYang1235 @ 2019-03-10 21:06:48
怎么@别人啊
by YueYang1235 @ 2019-03-10 21:16:05
@ 樱初音斗橡皮
by 小罐猹 @ 2019-04-16 19:43:07