问Java字符串快速排序偶尔工作吗？

EN

int pivot = r.nextInt(high-low+1)+low;

int pivot = low + (high - low) / 2;

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Random;

public class QuickSort {

    static String[] strings;

    public static void main(String[] args) {

        List<String> values = new ArrayList<>(26);
        for (int index = 0; index < 26; index++) {
            values.add(new String(new char[]{(char)(65 + index)}));
        }
        Collections.shuffle(values);

        strings = values.toArray(new String[values.size()]);
        System.out.println("Before");
        for (int i = 0; i < strings.length; i++) {
            System.out.print(strings[i] + " ");
        }
        System.out.println("");

        qsort(0, strings.length - 1);

        System.out.println("The array, quicksorted: ");
        for (int i = 0; i < strings.length; i++) {
            System.out.print(strings[i] + " ");
        }
        System.out.println("\n");
    }

    static void qsort(int low, int high) {
        int i = low, j = high;

        // Get the pivot element
        int pivot = low + (high - low) / 2;
        String value = strings[pivot];

        // Divide into two lists
        while (i <= j) {

            while (strings[i].compareTo(value) < 0) {
                i++;
            }

            while (strings[j].compareTo(value) > 0) {
                j--;
            }

            if (i <= j) {
                exchange(i, j);
                i++;
                j--;
            }
        }

        // Recursion
        if (low < j) {
            qsort(low, j);
        }
        if (i < high) {
            qsort(i, high);
        }
    }

    static void exchange(int i, int j) {
        String temp = strings[i];
        strings[i] = strings[j];
        strings[j] = temp;
    }

}

Before
N S B A F Z X J Q K V C L R W E H Y M U G I D P T O 
The array, quicksorted: 
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z 

Before
G U P Q D A W T R M E O X J S C I V Y F H L B N Z K 
The array, quicksorted: 
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z 

Before
D Z C B Q O K W X F V G R S A U P T H Y I E N L M J 
The array, quicksorted: 
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z 

Before
Q K H B W N J V C Y U O R P G I F D Z E L S A X M T 
The array, quicksorted: 
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z 

Before
R V P G E S C A H W X I T D Z B K Q F M U Y L J N O 
The array, quicksorted: 
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z 

Before
L O T E U D H N P J V I Q C X S Z W A R F K G Y B M 
The array, quicksorted: 
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z 

Before
I E J F U X P K R Q L S C O Y W G A Z B V M D H N T 
The array, quicksorted: 
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z 

Before
X L K T W E V J N Y G H O Q I M C P A R B F S U Z D 
The array, quicksorted: 
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z 

Before
U X N T K Q S V P F W C G Y O L A B E H J R D M Z I 
The array, quicksorted: 
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z 

Before
A J Z C M Y O Q F L K D P S X W N T I B H E R U V G 
The array, quicksorted: 
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z