Java 快速排序

package com.algorithms;import java.util.Arrays;import java.util.Random;public class QuickSort {private static int count = 0;public static  void quickSort(Integer[] arr, int l, int r) {if(l < r) {int p = randomPartition(arr, l, r);quickSort(arr, l, p - 1);quickSort(arr, p + 1, r);}}public static int randomPartition(Integer[] arr, int l, int r) {int p = getRandomIndex(l, r);exchange(arr, p, r);return partition(arr, l, r);}public static int partition(Integer[] arr, int l, int r) {int x = arr[r];int i = l - 1;for(int j = l; j < r; j++) {count++;if(arr[j] <= x) {i = i + 1;exchange(arr, i , j);}}exchange(arr, i + 1, r);return i + 1;}public static void exchange(Integer[] arr, int x, int y) {int temp = 0;temp = arr[x];arr[x] = arr[y];arr[y] = temp;}public static int getRandomIndex(int min, int max) {Random random = new Random(37);return random.nextInt(max)%(max-min+1) + min;}public static void main(String[] args) {Integer arr[] = {12, 2, 10, 16, 5, 6, 8, 1, 9, 18};//		Integer arr[] = new Integer[30000000];//		Random random = new Random(37);//		for(int i = 0; i < 30000000; i++) {//			arr[i] = random.nextInt(100000000)%(100000000 - 0 + 1)  + 0;//		}quickSort(arr, 0, arr.length - 1);System.out.println(Arrays.asList(arr));System.out.println(count);}}