手撕冒泡排序

public class BubbleSort {
    public void bubbleSort(int[] arr){
        if(arr==null||arr.length<2){
            return;
        }
        for (int i = arr.length-1; i >0 ; i--) {
            for (int j = 0; j <i ; j++) {
                if(arr[j]>arr[j+1]){
                    swap(arr,j,j+1);
                }
            }
        }
    }

    private void swap(int[] arr,int a,int b){
        int tmp=arr[a];
        arr[a]=arr[b];
        arr[b]=tmp;
    }

    @Test
    public void test(){
        int[] n=new int[]{4,3,2,7,1};
        bubbleSort(n);
        for (int i = 0; i <n.length ; i++) {
            System.out.println(n[i]);
        }
    }
}