Java实现快速排序算法的详细步骤解析

public class QuickSort {

    public static void quickSort(int[] arr, int low, int high) {
        if (arr == null || arr.length == 0 || low >= high) {
            return;
        }

        // 选择基准元素
        int pivotIndex = partition(arr, low, high);

        // 对基准元素左边的子序列递归排序
        quickSort(arr, low, pivotIndex - 1);

        // 对基准元素右边的子序列递归排序
        quickSort(arr, pivotIndex + 1, high);
    }

    private static int partition(int[] arr, int low, int high) {
        // 选择最后一个元素作为基准
        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;
    }

    public static void main(String[] args) {
        int[] arr = {5, 2, 9, 1, 6, 3, 8, 4, 7};
        int n = arr.length;

        quickSort(arr, 0, n - 1);

        System.out.println("排序后的结果：");
        for (int i : arr) {
            System.out.print(i + " ");
        }
    }
}