过不了 Subtask 1 求调

pair < long double , pair < long double , long double > > a[10005];
int n;
long double calc(long double x)
{
    long double maxx = -1e18;
    for(int i = 1 ; i <= n ; i++)
    {
        maxx = max(maxx , a[i].first * x * x + a[i].second.first * x + a[i].second.second);
    }
    return maxx;
}
void solve()
{
    read(n);
    for(int i = 1 ; i <= n ; i++)
    {
        read(a[i].first , a[i].second.first , a[i].second.second);
    }
    long double l = 0 , r = 1000;
    long double ans = 0;
    while(abs(r - l) > 1e-12)
    {
        long double lmid = (l + l + r) / 3.0;
        long double rmid = (l + r + r) / 3.0;
        if(calc(lmid) < calc(rmid))
        {
            r = rmid;
            ans = rmid;
        }
        else
        {
            l = lmid;
        }
    }
    cout << fixed << setprecision(4) << calc(ans) << endl;
}
signed main()
{
    int t;
    read(t);
	while(t--)
    {
        solve();
    }
	return 0;
}