数据结构的几种经典算法

http://www.sina.com.cn 2006年03月24日 10:20 太平洋电脑网

作者：treeroot

用Java语言实现的各种排序，包括插入排序、冒泡排序、选择排序、Shell排序、快速排序、归并排序、堆排序、SortUtil等。 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;ifor(int j=i;(j>0)&&(data[j]}

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;ii;j--){ if(data[j]SortUtil.swap(data,j,j-1); } } } } }

选择排序：

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;jinsertSort(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;ifor(int j=i;(j>=inc)&&(data[j]}

快速排序：

package org.rut.util.algorithm.support;

import org.rut.util.algorithm.SortUtil; /**

* @author treeroot * @since 2006-2-2 * @version 1.0 */

public class QuickSort implements SortUtil.Sort{

/* (non-Javadoc)

* @see org.rut.util.algorithm.SortUtil.Sort#sort(int[]) */

public void sort(int[] data) {

quickSort(data,0,data.length-1); }

private void quickSort(int[] data,int i,int j){ int pivotIndex=(i+j)/2; //swap

SortUtil.swap(data,pivotIndex,j);

int k=partition(data,i-1,j,data[j]); SortUtil.swap(data,k,j);

if((k-i)>1) quickSort(data,i,k-1); if((j-k)>1) quickSort(data,k+1,j); } /**

* @param data * @param i

* @param j * @return */

private int partition(int[] data, int l, int r,int pivot) { do{

while(data[++l]while((r!=0)&&data[--r]>pivot); SortUtil.swap(data,l,r); }

while(lSortUtil.swap(data,l,r); return l; } }

改进后的快速排序：

package org.rut.util.algorithm.support;

import org.rut.util.algorithm.SortUtil; /**

* @author treeroot * @since 2006-2-2 * @version 1.0 */

public class ImprovedQuickSort implements SortUtil.Sort {

private static int MAX_STACK_SIZE=4096; private static int THRESHOLD=10; /* (non-Javadoc)

* @see org.rut.util.algorithm.SortUtil.Sort#sort(int[]) */

public void sort(int[] data) {

int[] stack=new int[MAX_STACK_SIZE];

int top=-1; int pivot;

int pivotIndex,l,r;

stack[++top]=0;

stack[++top]=data.length-1;

while(top>0){

int j=stack[top--]; int i=stack[top--];

pivotIndex=(i+j)/2; pivot=data[pivotIndex];

SortUtil.swap(data,pivotIndex,j);

//partition l=i-1; r=j; do{

while(data[++l]while((r!=0)&&(data[--r]>pivot)); SortUtil.swap(data,l,r); }

while(lSortUtil.swap(data,l,r); SortUtil.swap(data,l,j);

if((l-i)>THRESHOLD){ stack[++top]=i; stack[++top]=l-1; }

if((j-l)>THRESHOLD){ stack[++top]=l+1; stack[++top]=j; } }

//new InsertSort().sort(data); insertSort(data); } /**

* @param data */

private void insertSort(int[] data) { int temp;

for(int i=1;ifor(int j=i;(j>0)&&(data[j]归并排序：

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]data[cur]=temp[i2++]; } } }

改进后的归并排序:

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;ifor(int j=i;(j>start) && data[j]} } 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;iSystem.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} }

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]if (queue[k]>queue[j]) //不用交换 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\\"merge\ };

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; } }