隨筆檔案(496)

插入排序：

package org.rut.util.algorithm.support;

import org.rut.util.algorithm.SortUtil;
/**
* @author treeroot
* @since 2006-2-2
* @version 1.0
*/
public class InsertSort implements SortUtil.Sort{

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

}

冒泡排序：

package org.rut.util.algorithm.support;

import org.rut.util.algorithm.SortUtil;

/**
* @author treeroot
* @since 2006-2-2
* @version 1.0
*/
public class BubbleSort 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++){
???????????? for(int j=data.length-1;j>i;j--){
???????????????? if(data[j]<data[j-1]){
???????????????????? SortUtil.swap(data,j,j-1);
???????????????? }
???????????? }
???????? }
???? }

}

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);
???????? }
???? }

}

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);
???????????? }
???????? }
???? }

堆排序：

package org.rut.util.algorithm.support;

import org.rut.util.algorithm.SortUtil;

/**
* @author treeroot
* @since 2006-2-2
* @version 1.0
*/
public class 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;
???????????? }
???????? }

???? }

}