543 - Goldbach's Conjecture

/***

            Bismillahir Rahmanir Rahim
            Read the name of Allah, who created you!!!
            Author : Shah Newaj Rabbi Shishir
            Department of CSE, City University, Bangladesh.

***/

#include <bits/stdc++.h>
using namespace std;

#define sf scanf
#define pf printf
#define scase sf ("%d",&tc)
#define sn sf ("%d",&n)
#define whilecase while (tc--)
#define eof while (cin >> n)
#define forloop for (pos=1; pos<=tc; pos++)
#define arrayloop (i=0; i<n; i++)
#define cinstr cin >> str
#define getstr getline (cin,str)
#define pcase pf ("Case %d: ",pos)
#define pb push_back

int num = 1500005;
bool check[1500005];

void sieve ()
{
    int i,j;

    check[0] = check[1] = true;

    for (i=4; i<=num; i+=2)
        check[i] = true;

    for (i=3; i*i<=num; i+=2)
        if (!check[i])
            for (j=i*i; j<=num; j+=2*i)
                check[j] = true;

    return;
}


int main (void)
{
    int n,i,h;
    bool k;

    sieve ();

    while (cin >> n && n)
    {
        h = n/2;
        k = false;

        for (i=2; i<=h; i++)
        {
            if (!check[i] && !check[n-i])
            {
                k = true;
                pf ("%d = %d + %d\n",n,i,n-i);
                break;
            }
        }

        if (k == false)
            pf ("Goldbach's conjecture is wrong.\n");
    }

    return 0;
}