1 /*2016.3.24 weilihua fengyutong*/
 2 #include <iostream>
 3 #include<ctime>
 4 #define Num 10000
 5 using namespace std;
 6 int DTGH_Sum(int a[],int n) //动态规划法求子段和函数
 7 {
 8     int sum = 0;
 9     int *b = (int *) malloc(n * sizeof(int));    //动态为数组分配空间
10     b[0] = a[0];
11     for(int i = 1; i < n; i++)
12     {
13         if(b[i-1] > 0)
14             b[i] = b[i - 1] + a[i];
15         else
16             b[i] = a[i];
17     }
18     for(int j = 0; j < n; j++)
19     {
20         if(b[j] > sum)
21             sum = b[j];
22     }
23     delete []b;        //释放内存
24     return sum;
25 }
26 int main()
27 {   int temp,b;
28     int sum=0;
29     int i;
30     int a1,a2;
31     int a[Num];
32     int length=0;
33     while (length==NULL||length == 0)//如果数组长度为空或零则请重新输入
34      {
35       cout<<"请输入数组长度：";
36       cin>>length;
37      }
38     cout<<"生成随机序列： "<<endl;
39     srand((unsigned)time(NULL));
40     for(i=0;i<length;i++)//产生随机序列
41     {
42         if(rand()%2==0)
43         {
44             a[i]=rand()%100;
45         }
46         else
47         {
48             a[i]=(-1)*rand()%100;
49         }
50             cout<<a[i]<<" ";
51     }
52     cout<<endl;
53     cout<<"此首尾相连的数组中最大子数组的和有以下几种可能："<<endl;
54     cout<<"第1种排列方式："<<endl;
55     for( i=0;i<length;i++)
56     {
57         cout<<a[i]<<"  ";
58     }
59     cout<<"最大子数组和为："<<DTGH_Sum(a,length)<<endl;
60     a1=DTGH_Sum(a,length);
61     for(b=1;b<length;b++)
62     {
63         temp=a[0];
64     for(i=1;i<=length;i++)
65      {
66         a[i-1]=a[i]; //将第一个数变为最后一个数
67
68      }
69        a[length-1]=temp;
70        cout<<"第"<<b+1<<"种排列方式："<<endl;
71        for( i=0;i<length;i++)
72        {
73            cout<<a[i]<<"  ";
74        }
75        cout<<"最大子数组和为："<<DTGH_Sum(a,length)<<endl;
76        if(DTGH_Sum(a,length)>=sum)
77        {
78            sum=DTGH_Sum(a,length);
79        }
80     }
81       a2=sum;
82       cout<<endl;
83       if(a1>=a2)
84       {
85           cout<<"综上，最大的子数组和为："<<a1<<endl;
86       }
87       else
88       {
89           cout<<"综上，最大的子数组和为："<<a2<<endl;
90       }
91     return 0;
92 } 

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