**这题**本来就是这样做的
by autoint @ 2017-10-27 12:41:01
- 补充:
#sqrt(2000000000)=44721.35955
by autoint @ 2017-10-27 13:00:56
我这么做也可以过:
```cpp
#include <iostream>
#include <cmath>
int n,p;
bool isprime(int x)
{
for(int i=2;i<=std::sqrt(x);i++)
{
if(i%x==0)return false;
}
return true;
}
int main()
{
std::cin>>n;
for(int p1=2;p1<=std::sqrt(n);p1++)
{
if(n%p1==0&&isprime(p1)&&isprime(n/p1))
{
std::cout<<std::max(p1,n/p1)<<std::endl;
return 0;
}
}
return 0;
}
```
by Alan_Zhao @ 2019-08-27 18:10:35