Java 快速排序

import java.util.Random;

/**
 * 
 * @author liebaorun liu
 *
 * @param <T>
 */

public class QuickSortUtil<T extends Comparable<T>> {
	
	
	public  void quickSort(T[] arr, int start, int end){
		

		if(start >= end) return;

		int middle = start;
		int pointerI = start;

		
		for( ; pointerI < end; pointerI++){
			if(arr[pointerI].compareTo(arr[end]) > 0){
				swap(arr,middle++,pointerI);
			}
		}

		swap(arr,middle,end);
		
		quickSort(arr,start,middle-1);
		quickSort(arr,middle+1,end);
	}
	
	private void swap(T[] arr, int i, int j){
		T temp = arr[i];
		arr[i] = arr[j];
		arr[j] = temp;
	}
	
	
	
	
	public static void main(String[] args){
		
		Integer[] arr = new Integer[100];
		
		QuickSortUtil<Integer> qut = new QuickSortUtil<Integer>();

		Random random = new Random();
		for(int i=0; i<arr.length; i++){
			arr[i] = new Integer(random.nextInt(20));
			System.out.print(arr[i] + "  ");
		}

		//int[] arr1 = new int[10];
		qut.quickSort(arr, 0, arr.length-1);
		
		System.out.println();
		
		for(int i=0; i<arr.length; i++){
			System.out.print(arr[i] + "  ");
		}
		
		qut.quickSort(arr, 0, arr.length-1);
		
		System.out.println();
		
		for(int i=0; i<arr.length; i++){
			System.out.print(arr[i] + "  ");
		}
		
	}
	
}