QuickSort实现

最新推荐文章于 2022-02-12 12:41:07 发布

原创最新推荐文章于 2022-02-12 12:41:07 发布 · 1.2k 阅读

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#integer #import #string #numbers #input #class

该博客展示了用Java实现快速排序算法的代码。定义了`QuickSort`类，包含`findPartition`方法用于寻找分区点，`quickSort`方法进行递归排序。在`main`方法中，从用户输入获取数据，调用排序方法并输出排序结果。

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import java.util.*;
import java.io.*;

public class QuickSort
{
private int findPartition(Comparable [] data,int min,int max)
{
  int left;
  int right;
  Comparable temp;
  Comparable partitionElement = data[min];

  left = min;
  right = max;

  while (left<right)
  {
   while(data[left].compareTo(partitionElement) <=0 && left<right)
    left++;
   while(data[right].compareTo(partitionElement)>0)
    right--;
   if(left<right)
   {
    temp = data[left];
    data[left] = data[right];
    data[right] = temp;
   }
  }

  temp = data[min];
  data[min] = data[right];
  data[right] = temp;

  return right;
}

public void quickSort (Comparable [] data,int s,int e)
{
  int p;
  if (s<e)
  {
   p=e;
   p=this.findPartition(data,s,p);
   this.quickSort(data,s,p-1);
   this.quickSort(data,p+1,e);
  }

}

public static void main (String [] args) throws IOException
{
  String inString ;
  StringTokenizer tokenizer;
  Integer [] elements;
  QuickSort qs = new QuickSort();

  BufferedReader in = new BufferedReader( new InputStreamReader(System.in));

  System.out.println("Please input the size: ");
  inString = in.readLine();
  elements = new Integer[Integer.parseInt(inString)];


  System.out.println("Enter the numbers of elements : ");
  inString = in.readLine();
  tokenizer = new StringTokenizer(inString);
  for (int i =0; i<elements.length && tokenizer.hasMoreTokens();i++)
  {
   elements[i] = Integer.parseInt(tokenizer.nextToken());
  }

  qs.quickSort(elements,0,elements.length-1);

  System.out.println("after sorted :");
  for (int i=0;i<elements.length;i++)
  {
   System.out.println(elements[i]);
  }

}
}