任意长度快排

快排定义：

             借鉴wiki对之的定义：http://en.wikipedia.org/wiki/Quicksort

 

代码实现：

public class Quicsort {
    
    
    public void _quickSort(Integer[] list, int low, int high) {
        if (low < high) {
            int middle = getMiddle(list, low, high);  
            _quickSort(list, low, middle - 1);        //递归调用
            _quickSort(list, middle + 1, high);       
        }
        //System.out.println(low);
        
    }

    public void quick(Integer[] str) {
        if (str.length > 0) {   
            _quickSort(str, 0, str.length - 1);
        }
    }
    
    private int getMiddle(Integer[] src, int start, int end) {
        int tmp = src[start];
        while (start < end) {
            while (start < end && src[end] >= tmp) {
                end--;
            }
            src[start] = src[end];
            while (start < end && src[start] <= tmp) {
                start++;
            }
            src[end] = src[start];
        }   
        src[start] = tmp; //一次排序
        return start;     //返回小于tmp的个数即实现分割
    }


}

import java.util.*; 
public class Test{  
      
   
      public static void main(String[] args) {  
          Scanner br=new Scanner(System.in);
          String f; 
          f=br.nextLine();     //把输入的字符串赋给f
          br.close();
          String  k[];
          k=f.split(" ");      //把f通过空格分割成字符串数组赋给字符串数组k
         
          ArrayList<Integer> y = new ArrayList<Integer>(); 
          for(int i=0;i<k.length;i++){
              String m=k[i];
              y.add(Integer.parseInt(m));
              // System.out.println(y.get(i)); 用于测试是否分割成功
              
          }
          Integer [] list ;
          list=(Integer[])y.toArray(new Integer[1]);  //把ArryList转换成Integer数组
          Quicsort qs=new Quicsort();  
             qs.quick(list);  
              for(int i=0;i<list.length;i++){  
                  System.out.print(list[i]+" ");  
              }  
               System.out.println();  

        }  
  
}