排序算法--快速排序

import java.util.Arrays;
import java.util.Random;

public class QuickSort {
	
	public static void quickSort(int[] arr,int left,int right) {
		if(left >= right) {
			return;
		}
		swap(arr,right,left+(int)(Math.random()*(right-left+1)));
		int[] p = partition(arr,left,right);
		quickSort(arr,left,p[0]-1);
		quickSort(arr,p[1]+1,right);
	}
	
	private static void swap(int[] arr,int a,int b) {
		int temp = arr[a];
		arr[a] = arr[b];
		arr[b] = temp;
	}
	
	private static int[] partition(int[] arr,int L,int R) {
		int left = L-1;
		int right = R;
		while(L