Yurttas/PL/OOL/Java/F/06/02/00/SortAscending.java

 1/**
 2 *  Copyright(C) 1998
 3 *  All Rights Reserved. Salih Yurttas, ZCubes, BitsOfCode Software Systems, Inc..
 4 *
 5 *  Permission to use, copy, modify, and distribute this
 6 *  software and its documentation for EDUCATIONAL purposes
 7 *  and without fee is hereby granted provided that this
 8 *  copyright notice appears in all copies.
 9 *
10 *  @date   : January 1, 1998.
11 *  @author : Salih Yurttas.
12 */
13
14
15public class SortAscending {
16
17  public static int partition(final int[] list,
18                              final int i,
19                              final int j) {
20
21    int middle = (i+j)/2;      // middle as the pivot
22
23    int pivot = list[middle];
24    list[middle] = list[i];
25    list[i] = pivot;
26    int p = i;
27
28    int temp;
29    for(int k=i+1; k<=j; k++)
30      if(list[k]<pivot) {      // elements less than pivot
31        temp = list[++p];      // replaced by list[++p]
32        list[p] = list[k];
33        list[k] = temp;
34      }
35    temp = list[i];            // pivot in list[p]
36    list[i] = list[p];
37    list[p] = temp;
38
39    return p;                  // return pivot position
40  }
41
42  public static void quick(final int[] list,
43                           final int i,
44                           final int n) {
45    if(i<n) {
46      int p = partition(list,
47                        i,
48                        n);   // p is the list pivot position
49      quick(list,
50            i,
51            p-1);
52      quick(list,
53            p+1,
54            n);
55    }
56  }
57
58}