筛法求质数啊。。。。。。
by gstdio @ 2018-07-17 09:59:14
@[清歌’](/space/show?uid=87378)
#include<iostream>
#include<cstdio>
#include<cmath>
using namespace std;
int judge(int x);
int main()
{
int N;
scanf("%d",&N);
for(int n=4;n<=N;n+=2)
{
for(int i=2;i<=n/2;i++)
{
if(judge(i)&&judge(n-i))
{
printf("%d=%d+%d\n",n,i,(n-i));
break;
}
}
}
return 0;
}
int judge(int x)
{
if(x<2) return 0;
for(int i=2;i<=sqrt(x);i++)
{
if(x%i==0) return 0;
}
return 1;
}
ok
by 清歌’ @ 2018-07-17 10:13:31