各种排序算法java实现

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;
}
}