Groovy example source code file (heapsort.java)

This example Groovy source code file (heapsort.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Groovy tags/keywords

ia, ia, ic, ic, im, im, n, n+1, n+1, numberformat, reflection, text

The Groovy heapsort.java source code

// $Id: heapsort.java,v 1.1 2004-05-23 06:37:41 bfulgham Exp $
// http://www.bagley.org/~doug/shootout/

import java.text.*;
import java.lang.reflect.Array;

public class heapsort {

    public static final long IM = 139968;
    public static final long IA =   3877;
    public static final long IC =  29573;

    public static void main(String args[]) {
	int N = Integer.parseInt(args[0]);
	NumberFormat nf = NumberFormat.getInstance();
	nf.setMaximumFractionDigits(10);
	nf.setMinimumFractionDigits(10);
	nf.setGroupingUsed(false);
	double []ary = (double[])Array.newInstance(double.class, N+1);
	for (int i=1; i<=N; i++) {
	    ary[i] = gen_random(1);
	}
	heapsort(N, ary);
	System.out.print(nf.format(ary[N]) + "\n");
    }

    public static long last = 42;
    public static double gen_random(double max) {
	return( max * (last = (last * IA + IC) % IM) / IM );
    }

    public static void heapsort(int n, double ra[]) {
	int l, j, ir, i;
	double rra;

	l = (n >> 1) + 1;
	ir = n;
	for (;;) {
	    if (l > 1) {
		rra = ra[--l];
	    } else {
		rra = ra[ir];
		ra[ir] = ra[1];
		if (--ir == 1) {
		    ra[1] = rra;
		    return;
		}
	    }
	    i = l;
	    j = l << 1;
	    while (j <= ir) {
		if (j < ir && ra[j] < ra[j+1]) { ++j; }
		if (rra < ra[j]) {
		    ra[i] = ra[j];
		    j += (i = j);
		} else {
		    j = ir + 1;
		}
	    }
	    ra[i] = rra;
	}
    }
}