зеркало из https://github.com/mozilla/gecko-dev.git
112 строки
3.3 KiB
Java
112 строки
3.3 KiB
Java
/* -*- Mode: Java; tab-width: 2; indent-tabs-mode: nil -*-
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*
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* The contents of this file are subject to the Mozilla Public
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* License Version 1.1 (the "License"); you may not use this file
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* except in compliance with the License. You may obtain a copy of
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* the License at http://www.mozilla.org/MPL/
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*
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* Software distributed under the License is distributed on an "AS
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* IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
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* implied. See the License for the specific language governing
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* rights and limitations under the License.
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*
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* The Original Code is the Grendel mail/news client.
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*
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* The Initial Developer of the Original Code is Netscape Communications
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* Corporation. Portions created by Netscape are
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* Copyright (C) 1997 Netscape Communications Corporation. All
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* Rights Reserved.
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*
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* Contributor(s):
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*/
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package calypso.util;
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/** Implements QuickSort, on an array of objects.
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An implementor of `Comparer' is passed in to compare two objects.
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*/
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public class QSort {
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private Comparer comp;
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/** Create a QSort object.
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One way to use this would with dynamic class creation:
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<PRE>
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QSort sorter = new QSort(new Comparer() {
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public int compare(Object a, Object b) {
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if (a.key == b.key) return 0;
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else if (a.key < b.key) return -1;
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else return 1;
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}
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});
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sorter.sort(array);
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</PRE>
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*/
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public QSort(Comparer c) {
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comp = c;
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}
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/** Sorts the array, according to the Comparer. */
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public void sort(Object[] list) {
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quicksort(list, 0, list.length - 1);
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}
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/** Sorts a subsequence of the array, according to the Comparer. */
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public void sort(Object[] list, int start, int end) {
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quicksort(list, start, end - 1);
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}
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private void quicksort(Object[] list, int p, int r) {
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if (p < r) {
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int q = partition(list,p,r);
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if (q == r) {
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q--;
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}
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quicksort(list,p,q);
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quicksort(list,q+1,r);
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}
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}
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private int partition (Object[] list, int p, int r) {
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Object pivot = list[p];
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int lo = p;
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int hi = r;
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while (true) {
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while (comp.compare(list[hi], pivot) >= 0 &&
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lo < hi) {
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hi--;
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}
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while (comp.compare(list[lo], pivot) < 0 &&
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lo < hi) {
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lo++;
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}
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if (lo < hi) {
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Object T = list[lo];
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list[lo] = list[hi];
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list[hi] = T;
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}
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else return hi;
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}
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}
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// public static void main(String argv[]) {
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// String array[] = { "7", "3", "0", "4", "5", "6", "2", "1" };
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// QSort sorter = new QSort(new Comparer() {
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// public int compare(Object a, Object b) {
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// int ai = Integer.parseInt((String) a);
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// int bi = Integer.parseInt((String) b);
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// if (ai == bi) return 0;
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// else if (ai < bi) return -1;
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// else return 1;
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// }
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// });
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// sorter.sort(array);
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// for (int i = 0; i < array.length; i++)
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// System.out.print(array[i] + " ");
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// System.out.println();
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// }
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}
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