https://vjudge.net/problem/POJ-2262
#include<iostream>
#include<cstdio>
#include<algorithm>
#include<cstring>
#include<cmath>
using namespace std;
const int N=1e6+10;
bool bk[N];
void prime()
{
memset(bk,false,sizeof bk);
for(int i=2;i<=sqrt(N);i++)
{
if(!bk[i])
{
for(int j=i+i;j<=N;j+=i)
bk[j]=true;
}
}
}
int main()
{
prime();
int n;
while(~scanf("%d",&n),n)
{
bool f=false;
for(int i=2;i<=n/2;i++)
{
if(!bk[i] && !bk[n-i])
{
f=true;
printf("%d = %d + %d\n",n,i,n-i);
break;
}
}
if(!f)
printf("Goldbach's conjecture is wrong.\n");
}
return 0;
}