public class DoublingRatio

{

    public static double timeTrial(int N)

    {

        int MAX=1000000;

        int[] a=new int[N];

        for(int i=0;i<N;i++)

            a[i]=StdRandom.uniform(-MAX,MAX);

        Stopwatch timer=new Stopwatch();

        int cnt=ThreeSum.count(a);

        return timer.elapsedTime();

    }

   

    public static void main(String[] args)

    {

       double prev=timeTrial(125);

       for (int N=250;true;N+=N)

       {

           double time=timeTrial(N);

           StdOut.printf("%6d %7.1f  ",N,time);

           StdOut.printf("%5.1f\n",time/prev);

           prev=time;

       }

    }

}