编辑代码

class Main {
    public static void bubbleSort(int [] arr) {
        if(arr == null || arr.length < 2) {
            return;
        }
        int N = arr.length;
        for(int end = N - 1; end >= 0; end--) {
            // 0 ~ end
            for(int second = 1; second <= end; second++) {
                if(arr[second - 1] > arr[second]) {
                    swap(arr, second - 1, second);
                }
            }
        }
    }

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

    public static void printArr(int[] arr) {
        for(int i = 0; i < arr.length; i++) {
            System.out.print(arr[i] + " ");
        }
    }

	public static void main(String[] args) {
       int[] arr = { 7, 1, 3, 5, 6, 8, 2 };
       bubbleSort(arr);
       printArr(arr);
	}
}