用Java实现几种常见的排序算法

　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;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); 
                } 
            } 
        } 
    }

}

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;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); 
            } 
        } 
    }

}

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]<pivot); 
           while((r!=0)&&data[--r]>pivot); 
           SortUtil.swap(data,l,r); 
        } 
        while(l<r); 
        SortUtil.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]<pivot); 
                while((r!=0)&&(data[--r]>pivot)); 
                SortUtil.swap(data,l,r); 
            } 
            while(l<r); 
            SortUtil.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;i<data.length;i++){             for(int j=i;(j>0)&&(data[j]<data[j-1]);j--){                 SortUtil.swap(data,j,j-1);             }         }           } } 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]<temp[i2])                 data[cur]=temp[i1++];             else                 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;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", "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;     } }