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 2006-9-2
  * @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 for(int j=i;(j>0)&&(data[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 2006-9-2
  * @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 for(int j=data.length-1;j>i;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 2009-2-2
  * @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 2009-2-2
  * @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 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 for(int j=i;(j>=inc)&&(data[j] 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 2009-2-2
  * @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(l 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 2006-9-2
  * @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(l 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 for(int j=i;(j>0)&&(data[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 2006-9-2
  * @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[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 2006-9-2
  * @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 for(int j=i;(j>start) && data[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 2006-9-2
  * @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 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 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] 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 2006-9-2
  * @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;
   }
  }

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