冒泡排序(java)

 
import java.util.Arrays;
 
public class BubbleSort {
    public static void main(String[] args) {
        int[] arr = {3, 9, -1, 10, -20};
        System.out.println(Arrays.toString(arr));
        //int[] arr = {1,2,3,4,5};
        bubbleSort(arr);
 
        System.out.println();
    }
 
    private static void bubbleSort(int[] arr) {
        int length = arr.length;
        int tem = 0;
        //是否需要交换
        boolean flag = false;
        for (int i = 0; i < length - 1; i++) {
            System.out.printf("第%d轮开始\n", i + 1);
            flag = false;
            //数值大的排到后边
            for (int j = 0; j < length - i - 1; j++) {
                if (arr[j] > arr[j + 1]) {
                    tem = arr[j + 1];
                    arr[j + 1] = arr[j];
                    arr[j] = tem;
                    flag = true;
                }
                System.out.println(Arrays.toString(arr));
            }
            //如果一次排序中没有方式过交换
            if (!flag) {
                break;
            }
        }
    }
}