prime factor

uva583.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 primes;
void sieve()
{
    FILL(is_prime,true);

    for(int i=4;i<1000001;i+=2) is_prime[i]=false;
    for(int i=3;i<1001;i+=2)
    {
        if(is_prime[i])
            for(int j=i*i;j*i<1000001;j++)
                is_prime[i*j]=false;
    }
    primes.pb(2);
    for(int i=3;i<1000001;i++)
        if(is_prime[i]) primes.pb(i);
}

int main()
{
    sieve();
    ll n;
    while(1)
    {
        cin>>n;
        if(n==0) break;
        if(n<0){
                cout<<n<<" = -1 x";
                n=-n;
        }
        else
               cout<<n<<" =";
        ll x=n;
        int nop=primes.size();
        rep(i,nop)
        {
            if(x<=1)
                break;
            while(x%primes[i]==0)
            {
                x=x/primes[i];
                cout<<" "<<primes[i];
                if(x>1) cout<<" x";
            }
        }
        if(x>1)
            cout<<" "<<x;
        cout<<endl;

    }
  return 0;
}