/*
 * @(#)ExtraStorageMergeSortAlgorithm.java  1.0 97/01/09 Jack Snoeyink
 *
 * Copyright (c) 1995 University of British Columbia
 *
 * 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.
 */

/**
 * A merge sort demonstration algorithm using extra space
 * SortAlgorithm.java, Thu Oct 27 10:32:35 1994
 *
 * @author Jack Snoeyink@cs.ubc.ca
 * @version 	1.0, 09 Jan 97
 * 
 * 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 ExtraStorageMergeSortAlgorithm extends SortAlgorithm
{
	void sort(int a[], int lo, int hi, int scratch[])
	{
		super.updateAllViews(lo, hi);
		
		if (super.stopRequested)
		{
			return;
		}
		
		if (lo >= hi)
		{
			return; /* a[lo] is sorted already   */
		}

		int mid = (lo + hi) / 2;
		sort(a, lo, mid, scratch); /* Sort sublist a[lo..mid]   */
		sort(a, mid + 1, hi, scratch); /* Sort sublist a[mid+1..hi] */

		if (super.stopRequested)
		{
			return;
		}

		// Merge results
		int k, t_lo = lo, t_hi = mid + 1;
		super.lowMarker = lo;
		super.hiMarker = hi;
		for (k = lo; k <= hi; k++)
		{
			/* Merge sorted sublists    */
			super.compares++;
			if ((t_lo <= mid) && ((t_hi > hi) || (a[t_lo] < a[t_hi])))
			{
				scratch[k] = a[t_lo++];
			} else
			{
				scratch[k] = a[t_hi++];
			}
			super.moves++;
			super.activeMarker = k;
			super.updateAllViews();
		}

		for (k = lo; k <= hi; k++)
		{
			a[k] = scratch[k]; /* Copy back to a   */
			super.moves++;
			super.activeMarker = k;
			super.updateAllViews();
		}
	}

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