题解

#include <bits/stdc++.h>
using namespace std;
bool a[10001];
int main()
{
    int n;
    cin >> n;
    for (int i=2;i<=n;i++)
    {
        if (a[i] == 0)
        {
            for (int j=i+i;j<=n;j+=i)
            {
                a[j] = 1;
            }
        }
    }
    for (int i=4;i<=n;i+=2)
    {
        for (int j=2;j<=i;j++)
        {
            if (a[j] == 0 && a[i-j] == 0)
            {
                cout << i << '=' << j << '+' << i-j << endl;
                break;
            }
        }
    }
    return 0;
}