飛艷小屋

選擇排序：

package org.rut.util.algorithm.support;

import org.rut.util.algorithm.SortUtil;

/**
?* @author treeroot
?* @since 2006-2-2
?* @version 1.0
?*/
public class SelectionSort implements SortUtil.Sort {

??? /*
???? * (non-Javadoc)
???? *
???? * @see org.rut.util.algorithm.SortUtil.Sort#sort(int[])
???? */
??? public void sort(int[] data) {
??????? int temp;
??????? for (int i = 0; i < data.length; i++) {
??????????? int lowIndex = i;
??????????? for (int j = data.length - 1; j > i; j--) {
??????????????? if (data[j] < data[lowIndex]) {
??????????????????? lowIndex = j;
??????????????? }
??????????? }
??????????? SortUtil.swap(data,i,lowIndex);
??????? }
??? }

}

Shell排序：

package org.rut.util.algorithm.support;

import org.rut.util.algorithm.SortUtil;

/**
?* @author treeroot
?* @since 2006-2-2
?* @version 1.0
?*/
public class ShellSort implements SortUtil.Sort{

??? /* (non-Javadoc)
???? * @see org.rut.util.algorithm.SortUtil.Sort#sort(int[])
???? */
??? public void sort(int[] data) {
??????? for(int i=data.length/2;i>2;i/=2){
??????????? for(int j=0;j<i;j++){
??????????????? insertSort(data,j,i);
??????????? }
??????? }
??????? insertSort(data,0,1);
??? }

??? /**
???? * @param data
???? * @param j
???? * @param i
???? */
??? private void insertSort(int[] data, int start, int inc) {
??????? int temp;
??????? for(int i=start+inc;i<data.length;i+=inc){
??????????? for(int j=i;(j>=inc)&&(data[j]<data[j-inc]);j-=inc){
??????????????? SortUtil.swap(data,j,j-inc);
??????????? }
??????? }
??? }

}

歸并排序：

package org.rut.util.algorithm.support;

import org.rut.util.algorithm.SortUtil;

/**
?* @author treeroot
?* @since 2006-2-2
?* @version 1.0
?*/
public class MergeSort implements SortUtil.Sort{

??? /* (non-Javadoc)
???? * @see org.rut.util.algorithm.SortUtil.Sort#sort(int[])
???? */
??? public void sort(int[] data) {
??????? int[] temp=new int[data.length];
??????? mergeSort(data,temp,0,data.length-1);
??? }
????
??? private void mergeSort(int[] data,int[] temp,int l,int r){
??????? int mid=(l+r)/2;
??????? if(l==r) return ;
??????? mergeSort(data,temp,l,mid);
??????? mergeSort(data,temp,mid+1,r);
??????? for(int i=l;i<=r;i++){
??????????? temp[i]=data[i];
??????? }
??????? int i1=l;
??????? int i2=mid+1;
??????? for(int cur=l;cur<=r;cur++){
??????????? if(i1==mid+1)
??????????????? data[cur]=temp[i2++];
??????????? else if(i2>r)
??????????????? data[cur]=temp[i1++];
??????????? else if(temp[i1]<temp[i2])
??????????????? data[cur]=temp[i1++];
??????????? else
??????????????? data[cur]=temp[i2++];???????????
??????? }
??? }

}

改進后的歸并排序:

package org.rut.util.algorithm.support;

import org.rut.util.algorithm.SortUtil;

/**
?* @author treeroot
?* @since 2006-2-2
?* @version 1.0
?*/
public class ImprovedMergeSort implements SortUtil.Sort {

??? private static final int THRESHOLD = 10;

??? /*
???? * (non-Javadoc)
???? *
???? * @see org.rut.util.algorithm.SortUtil.Sort#sort(int[])
???? */
??? public void sort(int[] data) {
??????? int[] temp=new int[data.length];
??????? mergeSort(data,temp,0,data.length-1);
??? }

??? private void mergeSort(int[] data, int[] temp, int l, int r) {
??????? int i, j, k;
??????? int mid = (l + r) / 2;
??????? if (l == r)
??????????? return;
??????? if ((mid - l) >= THRESHOLD)
??????????? mergeSort(data, temp, l, mid);
??????? else
??????????? insertSort(data, l, mid - l + 1);
??????? if ((r - mid) > THRESHOLD)
??????????? mergeSort(data, temp, mid + 1, r);
??????? else
??????????? insertSort(data, mid + 1, r - mid);

??????? for (i = l; i <= mid; i++) {
??????????? temp[i] = data[i];
??????? }
??????? for (j = 1; j <= r - mid; j++) {
??????????? temp[r - j + 1] = data[j + mid];
??????? }
??????? int a = temp[l];
??????? int b = temp[r];
??????? for (i = l, j = r, k = l; k <= r; k++) {
??????????? if (a < b) {
??????????????? data[k] = temp[i++];
??????????????? a = temp[i];
??????????? } else {
??????????????? data[k] = temp[j--];
??????????????? b = temp[j];
??????????? }
??????? }
??? }

??? /**
???? * @param data
???? * @param l
???? * @param i
???? */
??? private void insertSort(int[] data, int start, int len) {
??????? for(int i=start+1;i<start+len;i++){
??????????? for(int j=i;(j>start) && data[j]<data[j-1];j--){
??????????????? SortUtil.swap(data,j,j-1);
??????????? }
??????? }
??? }

}

package org.rut.util.algorithm.support;

import org.rut.util.algorithm.SortUtil;

/**
?* @author treeroot
?* @since 2006-2-2
?* @version 1.0
?*/
public class HeapSort implements SortUtil.Sort{

??? /* (non-Javadoc)
???? * @see org.rut.util.algorithm.SortUtil.Sort#sort(int[])
???? */
??? public void sort(int[] data) {
??????? MaxHeap h=new MaxHeap();
??????? h.init(data);
??????? for(int i=0;i<data.length;i++)
??????????? h.remove();
??????? System.arraycopy(h.queue,1,data,0,data.length);
??? }

???? private static class MaxHeap{?????????
????????
??????? void init(int[] data){
??????????? this.queue=new int[data.length+1];
??????????? for(int i=0;i<data.length;i++){
??????????????? queue[++size]=data[i];
??????????????? fixUp(size);
??????????? }
??????? }
????????
??????? private int size=0;

??????? private int[] queue;
????????????????
??????? public int get() {
??????????? return queue[1];
??????? }

??????? public void remove() {
??????????? SortUtil.swap(queue,1,size--);
??????????? fixDown(1);
??????? }
??????? //fixdown
??????? private void fixDown(int k) {
??????????? int j;
??????????? while ((j = k << 1) <= size) {
??????????????? if (j < size && queue[j]<queue[j+1])
??????????????????? j++;
??????????????? if (queue[k]>queue[j]) //不用交換
??????????????????? break;
??????????????? SortUtil.swap(queue,j,k);
??????????????? k = j;
??????????? }
??????? }
??????? private void fixUp(int k) {
??????????? while (k > 1) {
??????????????? int j = k >> 1;
??????????????? if (queue[j]>queue[k])
??????????????????? break;
??????????????? SortUtil.swap(queue,j,k);
??????????????? k = j;
??????????? }
??????? }

??? }

}

SortUtil：

package org.rut.util.algorithm;

import org.rut.util.algorithm.support.BubbleSort;
import org.rut.util.algorithm.support.HeapSort;
import org.rut.util.algorithm.support.ImprovedMergeSort;
import org.rut.util.algorithm.support.ImprovedQuickSort;
import org.rut.util.algorithm.support.InsertSort;
import org.rut.util.algorithm.support.MergeSort;
import org.rut.util.algorithm.support.QuickSort;
import org.rut.util.algorithm.support.SelectionSort;
import org.rut.util.algorithm.support.ShellSort;

/**
?* @author treeroot
?* @since 2006-2-2
?* @version 1.0
?*/
public class SortUtil {
??? public final static int INSERT = 1;
??? public final static int BUBBLE = 2;
??? public final static int SELECTION = 3;
??? public final static int SHELL = 4;
??? public final static int QUICK = 5;
??? public final static int IMPROVED_QUICK = 6;
??? public final static int MERGE = 7;
??? public final static int IMPROVED_MERGE = 8;
??? public final static int HEAP = 9;

??? public static void sort(int[] data) {
??????? sort(data, IMPROVED_QUICK);
??? }
??? private static String[] name={
??????????? "insert", "bubble", "selection", "shell", "quick", "improved_quick", "merge", "improved_merge", "heap"
??? };
????
??? private static Sort[] impl=new Sort[]{
??????????? new InsertSort(),
??????????? new BubbleSort(),
??????????? new SelectionSort(),
??????????? new ShellSort(),
??????????? new QuickSort(),
??????????? new ImprovedQuickSort(),
??????????? new MergeSort(),
??????????? new ImprovedMergeSort(),
??????????? new HeapSort()
??? };

??? public static String toString(int algorithm){
??????? return name[algorithm-1];
??? }
????
??? public static void sort(int[] data, int algorithm) {
??????? impl[algorithm-1].sort(data);
??? }

??? public static interface Sort {
??????? public void sort(int[] data);
??? }

??? public static void swap(int[] data, int i, int j) {
??????? int temp = data[i];
??????? data[i] = data[j];
??????? data[j] = temp;
??? }
}