/* * Copyright (C) 2009 E.Albert, P.Arenas, S.Genaim, G.Puebla, and D.Zanardini * https://costa.ls.fi.upm.es * * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program. If not, see <http://www.gnu.org/licenses/>. */ package series; /** * This class implements a sorting method based on the merge-sort algorithm. * * * @author E.Albert, P.Arenas, S.Genaim, and G.Puebla * */ public class MergeSort { public void msort(int[] data) { sort(data,0,data.length); } public void sort(int[] data, int from, int to) { int mid; if (from < to) { mid = (from + to) / 2; sort(data, from, mid); sort(data, mid + 1, to); merge(data, from, to, mid); } } public void merge(int[] data, int from, int to, int mid) { int i, subListFrom = from, subListTo = mid + 1; int scratch[] = new int[data.length]; // Merge two sorted sublists using a scratch array for (i = from; i <= to; i++) { if ((subListFrom <= mid) && ((subListTo > to) || data[subListFrom]>data[subListTo])) // (data.compare(subListFrom, subListTo) == data.at(subListTo)))) scratch[i] = data[subListFrom++]; else scratch[i] = data[subListTo++]; } // Copy values stored in scratch array back for (i = from; i <= to; i++) { data[i]=scratch[i]; } } }