import java.util.*;

public class JavaSort {

  // Different array sizes to use:
  static int[] arraySizes = {10000, 30000, 50000, 70000, 90000};

  public static void main (String[] argv)
  {
    try {
      // Obtain number of samples (trials) from command line.
      if ( (argv == null) || (argv.length != 1) ) {
        System.out.println ("Usage: JavaSort <numTrials>");
        System.exit(1);
      }

      int numTrials = Integer.parseInt (argv[0]);

      // Perform comparison with each array size.
      for (int i=0; i<arraySizes.length; i++) {

        // Get estimate using randomly generated data.
        double avgTimeTaken = performTrials (numTrials, arraySizes[i]);

        // Get theoretical running time.
        double theoretical = theoreticalTime (arraySizes[i]);

        // Print ratio.
        System.out.println ("Actual=" + avgTimeTaken + " theoretical=" + theoretical 
                            + " ratio=" + (avgTimeTaken/theoretical));
      }

    }
    catch (Exception e) {
      e.printStackTrace();
    }
  }

  static double theoreticalTime (int n)
  {
    // Java uses MergeSort:  O(n log(n))
    return (double) n * Math.log(n);
  }
  
  static double performTrials (int numTrials, int arraySize)
  {
    // Initialize array A.
    int[] A = new int [arraySize];
    for (int i=0; i<arraySize; i++)
      A[i] = i;

    // We will measure the total time taken over all trials.
    double totalTimeTaken = 0;

    // Repeat "numTrials" times:

    for (int n=0; n<numTrials; n++) {

      // Randomly permute elements.
      RandomPermutation.permute (A);

      // Start timing.
      double startTime = System.currentTimeMillis();

      // Sort.
      Arrays.sort (A);

      // Measure time taken.
      double timeTaken = System.currentTimeMillis() - startTime;

      // Accumulate, for average.
      totalTimeTaken += timeTaken;
      
    }
    
    // Return average time taken.
    return totalTimeTaken / numTrials;
  }
  

}