[算法] 冒泡排序

1. 概念

2. 举例

3. 分析

4. 代码

　　

    //在冒泡排序的过程中，关键字较小的记录好比水中的气泡逐趟向上漂浮，而关键字较大的记录好比石块往下沉，每一趟有一块“最大”的石头沉到水底。  
    #include <iostream>  
    using namespace std;  
      
    void busort(int a[],int size)  
    {  
        for(int i=0;i<size-1;i++)  
            for(int j=size-1;j>i;j--)  
            if(a[j]<a[j-1])  
            {  
                int temp=a[j];  
                a[j]=a[j-1];  
                a[j-1]=temp;  
            }  
    }  
      
    int main()  
    {  
        int a[]={12,36,24,85,47,30,53,91};  
        for(int i=0;i<8;i++)  
            cout<<a[i]<<" ";  
        cout<<endl;  
      
        busort(a,8);  
        for(int i=0;i<8;i++)  
            cout<<a[i]<<" ";  
        cout<<endl;  
      
        return 0;  
    } 

5. 代码说明

int a[]={12,36,24,85,47,30,53,91};

busort(a,8); 

复杂度计算 n*（n-1）/2

复杂度次数	i	j		初始数组a[]		一次冒泡后的数组a[]
1	0	7		12,36,24,85,47,30,53,91		12,36,24,85,47,30,53,91
2	0	6		12,36,24,85,47,30,53,91		12,36,24,85,47,30,53,91
3	0	5		12,36,24,85,47,30,53,91		12,36,24,85,30,47,53,91
4	0	4		12,36,24,85,30,47,53,91		12,36,24,30,85,47,53,91
5	0	3		12,36,24,85,30,47,53,91		12,36,24,30,85,47,53,91
6	0	2		12,36,24,30,85,47,53,91		12,24,36,30,85,47,53,91
7	0	1		12,24,36,30,85,47,53,91		12,24,36,30,85,47,53,91
8	1	7		12,24,36,30,85,47,53,91		12,24,36,30,85,47,53,91
9	1	6		12,24,36,30,85,47,53,91		12,24,36,30,85,47,53,91
10	1	5		12,24,36,30,85,47,53,91		12,24,36,30,47,85,53,91
11	1	4		12,24,36,30,47,85,53,91		12,24,36,30,47,85,53,91
12	1	3		12,24,36,30,47,85,53,91		12,24,30,36,47,85,53,91
13	1	2		12,24,30,36,47,85,53,91		12,24,30,36,47,85,53,91
14	2	7		12,24,30,36,47,85,53,91		12,24,30,36,47,85,53,91
15	2	6		12,24,30,36,47,85,53,91		12,24,30,36,47,53,85,91
16	2	5		12,24,30,36,47,53,85,91		12,24,30,36,47,53,85,91
17	2	4		12,24,30,36,47,53,85,91		12,24,30,36,47,53,85,91
18	2	3		12,24,30,36,47,53,85,91		12,24,30,36,47,53,85,91
19	3	7		12,24,30,36,47,53,85,91		12,24,30,36,47,53,85,91
20	3	6		12,24,30,36,47,53,85,91		12,24,30,36,47,53,85,91
21	3	5		12,24,30,36,47,53,85,91		12,24,30,36,47,53,85,91
22	3	4		12,24,30,36,47,53,85,91		12,24,30,36,47,53,85,91
23	4	7		12,24,30,36,47,53,85,91		12,24,30,36,47,53,85,91
24	4	6		12,24,30,36,47,53,85,91		12,24,30,36,47,53,85,91
25	4	5		12,24,30,36,47,53,85,91		12,24,30,36,47,53,85,91
26	5	7		12,24,30,36,47,53,85,91		12,24,30,36,47,53,85,91
27	5	6		12,24,30,36,47,53,85,91		12,24,30,36,47,53,85,91
28	6	7		12,24,30,36,47,53,85,91		12,24,30,36,47,53,85,91