Using Seive C++

include

using namespace std; using ll = long long; ll mx = 1e5; vector cntDiv(mx+1);

void solve () {

ll n;
cin >> n;

for (ll i=1; i<=mx; i++){
    ll div;
    if(i%2 == 0) {
        div = cntDiv[i/2] * cntDiv[i+1];
    }else{
        div = cntDiv[i] * cntDiv[(i+1)/2];
    }
    if(div>n){
        cout << (i*(i+1)) / 2 << "\n";
        return;
    }
}

}

int main () {

 for (ll i=1; i<=mx; i++) {
     for (ll j=i; j<=mx; j+=i) {
         cntDiv[j]++;
     }
 }

 ll t;
 cin >> t;
 while ( t--) {
    solve();
 }

}