prime no problem with sieve erotheses,easy one

uva543_AC.cpp

/*
** id :template
** author : swap_coder
** time:
*/


#include<vector>
#include<algorithm>
#include<cstdio>
#include<cstring>
#include<cmath>
#include <iostream>
#include <map>
#include <queue>
#include <set>
#include <string>
#include <cstdlib>
#include <stack>
using namespace std;

#define fi(i,a,b) for(int i=(int)a;i<=(int)b;i++)
#define fd(i,a,b) for(int i=(int)a;i>=(int)b;i--)
#define rep(i,n)  for(int i=0;i<n;i++)
#define SET(a) memset(a,-1,sizeof(a))
#define ALL(a) a.begin(),a.end()
#define CLR(a) memset(a,0,sizeof(a))
#define FILL(a,v) memset(a,v,sizeof(a))
#define READ(f) freopen(f, "r", stdin)
#define WRITE(f) freopen(f, "w", stdout)
#define INF (1<<29)
#define EPS 1e-9
#define PI acos(-1.0)
//stl
 #define sz(a) int((a).size())
 #define pb push_back
 #define all(c) ((c).begin(),(c).end())
 #define tr(c,i) for(typeof((c).begin()) i = (c).begin(); i != (c).end(); i++)
 #define present(c,x) ((c).find(x) != (c).end())
 #define cpresent(c,x) (find(all(c),x) != (c).end())
 #define pf printf
 #define sf scanf


typedef long long ll;
typedef vector<int> vi;
typedef pair<int, int> ii;
typedef vector<ii>    vii;
typedef vector<vi> vvi;
typedef vector<vii> vvii;
typedef map<string,int> msi;

bool is_prime[1000001];
vi prime;
void sieve()
{
    memset(is_prime,true,sizeof is_prime);
    for(int i=2;i<1000001;i+=2)
        is_prime[i]=false;
    prime.pb(2);
    for(int i=3;i<=1000;i+=2)
    {
        if(is_prime[i])
        {
            for(int j=i;i*j<=1000001;j++)
                is_prime[j*i]=false;
            prime.pb(i);
        }
    }
    for(int i=1001;i<=1000000;i+=2)
    {
        if(is_prime[i])
            prime.pb(i);
    }
}
int main()
{

    sieve();
    //cout<<sz(prime);
  while(1)
    {
        int n;
        cin>>n;
        if(n==0 ) break;
        bool flag=false;
        int no;
        for(int i=1;i<sz(prime);i++)
        {
            if(flag || prime[i]>n)
                break;
            if(is_prime[n-prime[i]])
               {
                 flag=true;
                 no=prime[i];
               }
        }
        if(flag)
            cout<<n<<" = "<<no<<" + "<<n-no<<endl;
        else
            cout<<"Goldbach's conjecture is wrong."<<endl;
    }

	return 0;
}