我试图实现快速排序算法，但我有困难做它。我认为问题是在分区方法中，我把数组的第一个元素作为枢轴，并且我使用一个指针，它把所有较小的值放在数组的左边，最后把枢轴放在中间。谢谢您。
我的输入是：{42,12,52,1,34,31,0,3}但是我得到了：12,31,1,42,0,3,52,34

public static void quickSort(int[] A) {
        quickSort(A, 0, A.length - 1);
    }

    private static int[] quickSort(int[] A, int low, int high) {
        if (low < high) { // if there is still at least 1 element left in the array
            int p = partition(A, low, high);
            quickSort(A, low, p - 1);
            quickSort(A, p + 1, high);
        }
        return A;
    }

    private static int partition(int[] A, int low, int high) {
        int pointer = low + 1;
        int temp = 0;

        for (int i = low + 1; i <= high; i++) {
            if (A[i] < A[low]) {    // if a num is less than pivot, then put to left
                temp = A[pointer];
                A[pointer] = A[i];
                A[i] = temp;
                pointer++;
            }
            temp = A[pointer - 1];
            A[pointer - 1] = A[low];
            A[low] = temp;
        }
        return pointer - 1;
    }