java排序之冒泡排序

Posted 2020-10-22 g177w

代码：

 1 public class Test {
 2     public static int[] bublle_sort(int a[]){
 3         for (int i = 0; i < a.length-1; i++) {
 4             boolean exchange = false;
 5             for (int j = 0; j < a.length-i-1; j++) {
 6                 if (a[j+1]<a[j]){
 7                     int tmp = a[j];
 8                     a[j] = a[j+1];
 9                     a[j+1]=tmp;
10                     exchange = true;
11                 }
12             
13             }
14             if (exchange = false){
15                 break;
16             }
17         }
18         return a;
19     }
20 
21 public static void main(String[] args) {
22     //冒泡排序
23     System.out.println("************before bublle_sort**************");
24     int a[] = new int[5];
25     for (int i = 0; i < a.length; i++) {
26         a[i] = (int)(Math.random()*100);
27         System.out.println("原始数据:"+a[i]);
28     }
29     System.out.println("************after bublle_sort**************");
30     bublle_sort(a);
31     for (int i = 0; i < a.length; i++) {
32         System.out.println(a[i]);
33     }
34         
35 }

冒泡排序的时间复杂度位O(n^2),但是理想情况下为O(n)，记忆口诀：外管轮流内管排