Class - 28 : Task - 2

#include<bits/stdc++.h>
using namespace std;
typedef long long int ll;
const int mx=1e6+123;
bitset<mx> is_prime;
vector<ll>primes;
set<ll>st;
void prime_gen(ll n)
{
    is_prime[2]=1;
    for(ll i=3;i<=n;i+=2) is_prime[i]=1;
    for(ll i=3;i*i<=n;i+=2)
    {
        if(is_prime[i]==1)
        {
            for(ll j=i*i;j<=n;j+=2*i)
            {
                is_prime[j]=0;
            }
        }
    }
    primes.push_back(2);
    for(int i=3;i<=n;i+=2)
    {
        if(is_prime[i]==1) primes.push_back(i);
    }
}
vector<ll> find_prime_fact(ll n)
{
    vector<ll>v;
    for(auto prime:primes)
    {
        if(1ll * prime*prime>n) break;
        if(n%prime==0)
        {
            v.push_back(prime);
            while(n%prime==0)
            {
                n/=prime;
            }
        }
    }
    if(n>1) v.push_back(n);
    return v;
}
int main()
{
    prime_gen(1e6);
    ll t;
    cin>>t;
    for(ll i=1;i<=t;i++)
    {

        ll n;
        cin>>n;
        set<ll>st;
        while(n--)
        {
            vector<ll>v;
            ll a;
            cin>>a;
            v=find_prime_fact(a);
            for(auto u:v) st.insert(u);

        }
        cout<<"Case #"<<i<<": "<< st.size()<<endl;
        for(auto u:st ) cout<<u<<endl;
    }
}