/*
 * @(#)HeapSortAlgorithm.java	1.0 95/06/23 Jason Harrison
 *
 * 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 heap sort demonstration algorithm
 * SortAlgorithm.java, Thu Oct 27 10:32:35 1994
 *
 * @author Jason Harrison@cs.ubc.ca
 * @version 	1.0, 23 Jun 1995
 * 
 * 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 HeapSortAlgorithm extends SortAlgorithm
{
	void sort(int a[])
	{
		int N = a.length;
		// Build the heap
		for (int k = N / 2; k > 0; k--)
		{
			downheap(a, k, N);
			super.updateAllViews();
		}
		
		// Sort the data
		super.hiMarker = N;
		do
		{
			if (super.stopRequested)
			{
				return;
			}
			
			int T = a[0];
			a[0] = a[N - 1];
			a[N - 1] = T;
			super.moves++;
			N = N - 1;
			super.lowMarker = N;
			super.updateAllViews();
			
			downheap(a, 1, N);
		} while (N > 1);
	}

	void downheap(int a[], int k, int N)
	{
		int T = a[k - 1];
		super.other++;
		while (k <= N / 2)
		{
			if (super.stopRequested)
			{
				return;
			}
			
			int j = k + k;
			super.compares++;
			if ((j < N) && (a[j - 1] < a[j]))
			{
				j++;
			}
			super.compares++;
			if (T >= a[j - 1])
			{
				break;
			} else
			{
				a[k - 1] = a[j - 1];
				super.moves++;
				super.activeMarker = k-1;
				k = j;
			}
			super.updateAllViews();
		}
		a[k - 1] = T;
		super.moves++;
		super.updateAllViews();
	}
}