LightOj 1220 - Mysterious Bacteria

#include<cstdio>
#include<cstring>
#include<cmath>
#include<vector>

#define sf scanf
#define pf printf
#define limit 1000005
#define psb push_back

using namespace std;

typedef long long LL;

int prime[(limit >> 6) + 1] , plen;

#define setbit(n) (prime[n>>6] |= (1 << ((n>>1) & 31)))
#define checkbit(n) (prime[n>>6] & (1 << ((n>>1) & 31)))

vector<LL>prm;

void sieve()
{
    LL i,j;

    for(i=3; i*i<=limit; i+=2)
    {
        if(!checkbit(i))
        {
            for(j=i*i;j<=limit;j+=i+i)
            {
                setbit(j);
            }
        }
    }

    prm.psb(2);

    for(i=3; i<=limit; i+=2)
    {
        if(!checkbit(i))
        {
            prm.psb(i);
        }
    }

    plen = prm.size();
}

int factorize(LL n)
{
    int count_factor=0, mini=100000;

    for(int i=0;i<plen and prm[i]*prm[i]<=n; i++)
    {
        if(!(n%prm[i]))
        {
            count_factor=0;

            while(!(n%prm[i]))
            {
                count_factor++;
                n/=prm[i];
                if(n==0 or n==1)break;
            }

            mini = min(mini, count_factor);
        }
    }

    if(n > 1)
    {
        mini=1;
    }

    return mini;
}

int main()
{
    sieve();
    int t,tc=0;
    sf("%d",&t);
    LL num;

    while(t--)
    {
        sf("%lld",&num);

        bool fl=false;

        if(num < 0)
        {
            fl=true;
            num*=-1;
        }

        int res = factorize(num);

        if(fl)
        {
            while(!(res&1))
            {
                res/=2;
            }
        }

        pf("Case %d: %d\n",++tc,res);
    }

    return 0;
}