java 写一个快速排序

好的，下面给出Java实现的快速排序代码：

public class QuickSort {
    public static void quickSort(int[] arr, int low, int high) {
        if (low < high) {
            int pivotIndex = partition(arr, low, high);
            quickSort(arr, low, pivotIndex - 1);
            quickSort(arr, pivotIndex + 1, high);
        }
    }

    private static int partition(int[] arr, int low, int high) {
        int pivot = arr[high];
        int i = low - 1;
        for (int j = low; j < high; j++) {
            if (arr[j] < pivot) {
                i++;
                swap(arr, i, j);
            }
        }
        swap(arr, i + 1, high);
        return i + 1;
    }

    private static void swap(int[] arr, int i, int j) {
        int temp = arr[i];
        arr[i] = arr[j];
        arr[j] = temp;
    }
}

使用方法：

int[] arr = {4, 3, 6, 1, 2, 5};
QuickSort.quickSort(arr, 0, arr.length - 1);
System.out.println(Arrays.toString(arr));

输出结果为：[1, 2, 3, 4, 5, 6]