package username.median;

import java.util.Vector;
import java.io.PrintWriter;
import java.util.Random;

public class TestMedian
{
  public static void main(String[] args)
  {
    PrintWriter pen = new PrintWriter(System.out, true);
    boolean ok = true;
    Random r = new Random();
    IntegerComparator c = new IntegerComparator();
    for (int size = 1; size < 65; size++) {

      // Build a 'random' vector with no duplicates
      Vector<Integer> vec = new Vector<Integer>();
      int val = r.nextInt(100);
      for (int i = 0; i < size; i++) {
        val = val + 1 + r.nextInt(10);
        vec.add(new Integer(val));
      } // for i
      IVUtils.permute(vec);

      // Find the median.
      Integer median = Median.median(vec, c);

      // Determine whether or not it's really the median by counting
      // smaller and larger elements.
      int smaller = 0;
      int larger = 0;
      for (int i = 0; i < size; i++) {
        int tmp = c.compare(vec.get(i), median);
        if (tmp < 0) { ++smaller; }
        if (tmp > 0) { ++larger; }
      } // for
      if ((larger == smaller) || (larger == smaller-1)) {
        // OK
      }
      else {
        ok = false;
        pen.println("In " + vec);
        pen.println("  median returned " + median);
        pen.println("  there are " + smaller + " smaller values.");
        pen.println("  there are " + larger + " larger values.");
      }
    } // for size

    // If no errors were detected, report success.
    if (ok) {
      pen.println("No errors detected.");
    }
  } // main(String[])

} // class TestMedian