冒泡排序

 int[] arr = new int[]{2, 5, 1, 5, 3, 6, 1, 52, 10, 20};
    /**
     * 冒泡排序
     */
    @Test
    public void testBubbleSort() {
        System.out.println(Arrays.toString(arr));
        int tmp = 0;
        for (int i = 0; i < arr.length - 1; i++) {
            for (int j = 0; j < arr.length - i - 1; j++) {
                if (arr[j] > arr[j + 1]) {
                    tmp = arr[j];
                    arr[j] = arr[j + 1];
                    arr[j + 1] = tmp;
                }
            }
        }
        System.out.println(Arrays.toString(arr));
    }

选择排序

 int[] arr = new int[]{2, 5, 1, 5, 3, 6, 1, 52, 10, 20};
    /**
     * 选择排序
     */
    @Test
    public void testSelectSort() {
        int tmp = 0;
        System.out.println(Arrays.toString(arr));
        for (int i = 0; i < arr.length; i++) {
            for (int j = i + 1; j < arr.length; j++) {
                if (arr[i] > arr[j]) {
                    tmp = arr[i];
                    arr[i] = arr[j];
                    arr[j] = tmp;
                }
            }
        }
        System.out.println(Arrays.toString(arr));
    }

快速排序

  int[] arr = new int[]{2, 5, 1, 5, 3, 6, 1, 52, 10, 20};
    /**
     * 快速排序
     */
    @Test
    public void testQuickSort() {

        System.out.println(Arrays.toString(arr));
        this.sort(arr);
        System.out.println(Arrays.toString(arr));

    }

    private void sort(int[] arr) {
        int tmp = 0;
        for (int i = 1; i <= arr.length / 2; i++) {
            for (int j = i; j < arr.length - i + 1; j++) {
                if (arr[i - 1] > arr[j]) {
                    tmp = arr[i - 1];
                    arr[i - 1] = arr[j];
                    arr[j] = tmp;
                }
                if (arr[arr.length - i] < arr[arr.length - j - 1]) {
                    tmp = arr[arr.length - i];
                    arr[arr.length - i] = arr[arr.length - j - 1];
                    arr[arr.length - j - 1] = tmp;
                }
            }
        }
    }