package algs21;
import stdlib.*;
import java.awt.Font;
/* ***********************************************************************
 *  Compilation:  javac ZShellBars.java
 *  Execution:    java ZShellBars N
 *  Dependencies: StdDraw.java
 *
 *  Shellsor N random real numbers between 0 and 1, visualizing
 *  the results by ploting bars with heights proportional to the values.
 *
 *  % java ZShellBars 150
 *
 *************************************************************************/

public class XBarsShell {
  private static final int FF = 4;


  public static void sort(double[] a) {
    int N = a.length;
    int k = 1;
    int h = 1;
    while (h < N/3) {
      h = 3*h + 1;
      k++;
    }
    show(a, k, "input");

    while (h >= 1) {
      for (int i = h; i < N; i++) {
        for (int j = i; j >= h && less(a[j], a[j-h]); j -= h) {
          exch(a, j, j-h);
        }
      }
      if (h < N) show(a, --k, h + "-sorted");
      h = h/3;
    }
  }

  private static void show(double[] a, int k, String message) {
    for (int i = 0; i < a.length; i++) {
      StdDraw.setPenColor(StdDraw.BLACK);
      StdDraw.line(i, FF*k, i, FF*k + a[i]*(FF-1));
    }
    StdDraw.setPenColor(StdDraw.BOOK_RED);
    StdDraw.text(0, FF*k - .3, message);
  }

  private static boolean less(double v, double w) {
    return v < w;
  }

  private static void exch(double[] a, int i, int j) {
    double t = a[i];
    a[i] = a[j];
    a[j] = t;
  }


  public static void main(String[] args) {
    args = new String[] { "120" };
    int N = Integer.parseInt(args[0]);
    int k = (int) Math.round(Math.log(N) / Math.log(3));
    StdDraw.show(0);
    StdDraw.setCanvasSize(756, 900);
    StdDraw.setFont(new Font("SansSerif", Font.PLAIN, 9));
    StdDraw.setXscale(-1, N+1);
    StdDraw.setYscale(-1, (1+FF)*k);
    StdDraw.setPenRadius(.005);
    sort (ArrayGenerator.doubleRandomUnique (N));
    //sort (ArrayGenerator.partiallySortedUnique (N));
    //sort (ArrayGenerator.sortedUnique (N));
    //sort (ArrayGenerator.reverseSortedUnique (N));
    StdDraw.show(0);
  }
}