import java.applet.Applet;
import java.awt.*;
import java.util.Random;

public class Msort extends Applet 
  {
    static int N = 10000;
    static int dotsize = 4;
    static Graphics g;

    static void clear(Color c)
      { 
        int h = g.getClipRect().height;
        int w = g.getClipRect().width;
        g.setColor(c);
        g.fillRect(0, 0, w, h);
      }
    static void paint(int i, double x, Color c)
      { 
        int h = g.getClipRect().height;
        int w = g.getClipRect().width;
        g.setColor(c);
        g.fillOval( (i*w)/(N+N), h - (int) (x*h), dotsize, dotsize);
      }
    static void exch(double [] a, int i, int j)
      { double t = a[i]; a[i] = a[j]; a[j] = t;
        paint(i, a[j], Color.white);
        paint(j, a[i], Color.white);
        paint(i, a[i], Color.black);
        paint(j, a[j], Color.black);
      }
    static boolean less(double [] a, int i, int j)
      { 
        paint(i, a[i], Color.red);
        paint(j, a[j], Color.red);
        return a[i] < a[j];
      }
    static void merge(double[] a, int l, int m, int r)
      { int i, j, k;
        for (i = m+1; i > l; i--) exch(a, N+i-1, i-1);
        for (j = m; j < r; j++) exch(a, N+r+m-j, j+1);
        for (k = l; k <= r; k++)
          if (less(a, N+i, N+j))
            exch(a, k, N+(i++)); else exch(a, k, N+(j--));
      }
    static void mergesort(double[] a, int l, int r)
      { int m = (r+l)/2;
        if (r <= l) return;
        mergesort(a, l, m);
        mergesort(a, m+1, r);
        merge(a, l, m, r);
      }
    static void mergesortBU(double[] a, int l, int r)
      { int i, m;
        for (m = 1; m < r-l; m = m+m)
          for (i = l; i <= r-m; i += m+m)
            if (i+m+m-1 < r)
              merge(a, i, i+m-1, i+m+m-1);
            else
              merge(a, i, i+m-1, r);
      }
    static void arrayInitRand(double a[], int l, int r)
      { int i; 
        for (i = l; i <= r; i++)
          {
            a[i] =  Math.random(); 
            paint(i, a[i], Color.black);
          }
      }
    static void arrayInitRev(double a[], int l, int r)
      { int i; 
        for (i = l; i <= r; i++)
          {
            a[i] =  ((double) (r-i))/((double) (r-l)); 
            paint(i, a[i], Color.black);
          }
      }
    public void paint(Graphics page)
      {
        int alg = Integer.parseInt(getParameter("algorithm"));
        double[] a = new double[N+N];
        g = page;
        N = Integer.parseInt(getParameter("N"));
        dotsize = Integer.parseInt(getParameter("dotsize"));
        arrayInitRand(a, 0, N-1);
        if (alg == 1)
          {
            mergesort(a, 0, N-1);
            clear(Color.lightGray); arrayInitRand(a, 0, N-1);
            mergesortBU(a, 0, N-1);
          }
      }
  }