/*
 * @(#)QubbleSortAlgorithm.java	1.0 95/06/26 Jim Boritz
 *
 * Copyright (c) 1995 UBC Microsystems, Inc. All Rights Reserved.
 *
 * Permission to use, copy, modify, and distribute this software
 * and its documentation for NON-COMMERCIAL purposes and without
 * fee is hereby granted provided that this copyright notice
 * appears in all copies. Please refer to the file "copyright.html"
 * for further important copyright and licensing information.
 *
 * UBC MAKES NO REPRESENTATIONS OR WARRANTIES ABOUT THE SUITABILITY OF
 * THE SOFTWARE, EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
 * TO THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
 * PARTICULAR PURPOSE, OR NON-INFRINGEMENT. UBC SHALL NOT BE LIABLE FOR
 * ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING OR
 * DISTRIBUTING THIS SOFTWARE OR ITS DERIVATIVES.
 */

/**
 * An quick sort with buble sort speedup  demonstration algorithm
 * SortAlgorithm.java, Thu Oct 27 10:32:35 1994
 *
 * @author Jim Boritz
 * @version 	1.6, 26 Jun 1995
 */
/**
 * 19 Feb 1996: Fixed to avoid infinite loop discoved by Paul Haberli.
 *              Misbehaviour expressed when the pivot element was not unique.
 *              -Jason Harrison
 *
 * 21 Jun 1996: Modified code based on comments from Paul Haeberli, and
 *              Peter Schweizer (Peter.Schweizer@mni.fh-giessen.de).  
 *              Used Daeron Meyer's (daeron@geom.umn.edu) code for the
 *              new pivoting code. - Jason Harrison
 *
 * 09 Jan 1998: Another set of bug fixes by Thomas Everth (everth@wave.co.nz)
 *              and John Brzustowski (jbrzusto@gpu.srv.ualberta.ca).
 *              
 *   
 * 27 Nov 2006: (bwbecker@uwaterloo.ca) Changed the overall architecture to
 * use model-view-controller.  Re-examined algorithm to ensure that counting
 * was consistent across all algorithms (the quicksorts used to ignore most
 * of the comparisons in the partitioning, for example).
 */
class QubbleSortAlgorithm extends SortAlgorithm
{
	void bsort(int a[], int lo, int hi)
	{
		super.updateAllViews(lo, hi);
		for (int j = hi; j > lo; j--)
		{
			for (int i = lo; i < j; i++)
			{	
				super.activeMarker = i;
				super.compares++;
				if (a[i] > a[i + 1])
				{
					int T = a[i];
					a[i] = a[i + 1];
					a[i + 1] = T;
					super.moves++;
					super.updateAllViews();
				}
				
				if (super.stopRequested)
				{
					return;
				}
			}
		}
		super.activeMarker = -1;
	}

	void sort(int a[], int lo0, int hi0)
	{
		int lo = lo0;
		int hi = hi0;
		super.updateAllViews(lo, hi);

		/*
		 *  Bubble sort if the number of elements is less than 6 
		 */
		if ((hi - lo) <= 6)
		{
			bsort(a, lo, hi);
			return;
		}

		/*
		 *  Pick a pivot and move it out of the way
		 */
		int pivot = a[(lo + hi) / 2];
		a[(lo + hi) / 2] = a[hi];
		a[hi] = pivot;
		super.other += 3;

		while (lo < hi)
		{
			/*
			 *  Search forward from a[lo] until an element is found that
			 *  is greater than the pivot or lo >= hi 
			 */
			super.compares++;
			while (a[lo] <= pivot && lo < hi)
			{
				lo++;
				super.compares++;
			}

			/*
			 *  Search backward from a[hi] until element is found that
			 *  is less than the pivot, or hi <= lo 
			 */
			super.compares++;
			while (pivot <= a[hi] && lo < hi)
			{
				hi--;
				super.compares++;
			}

			/*
			 *  Swap elements a[lo] and a[hi]
			 */
			if (lo < hi)
			{
				int T = a[lo];
				a[lo] = a[hi];
				a[hi] = T;
				super.moves++;
			}
			super.updateAllViews();

			if (stopRequested)
			{
				return;
			}
		}

		/*
		 *  Put the median in the "center" of the list
		 */
		a[hi0] = a[hi];
		a[hi] = pivot;
		super.moves += 2;
		super.updateAllViews();

		/*
		 *  Recursive calls, elements a[lo0] to a[lo-1] are less than or
		 *  equal to pivot, elements a[hi+1] to a[hi0] are greater than
		 *  pivot.
		 */
		sort(a, lo0, lo - 1);
		sort(a, hi + 1, hi0);
	}

	void sort(int a[])
	{
		sort(a, 0, a.length - 1);
		super.updateAllViews(-1, -1);
	}
}