1 #include <iostream>
 2 using namespace std;
 3
 4 int Partiton(int array[],int start,int end)
 5 {
 6     int i=start;
 7     int j=end;
 8     int k=0;
 9     int base=array[0];
10     while(i<j)
11     {
12         if(i<j&&base<=array[j])
13             j--;
14
15         if(i<j)
16         {
17             array[i]=array[j];
18             i++;
19         }
20
21         if(i<j&&base>array[i])
22             i++;
23
24         if(i<j)
25         {
26             array[j]=array[i];
27             j--;
28         }
29     }
30
31     array[i]=base;
32
33     return i;
34 }
35
36 int FindTopK(int array[],int start,int end,int k)
37 {
38     int startindex=start;
39     int endindex=end;
40     int index=Partiton(array,startindex,endindex);
41
42
43
44     while(index!=k-1)
45     {
46         if(index>k-1)
47         {
48             endindex=index-1;
49             index=Partiton(array,startindex,endindex);
50         }
51         else
52         {
53             startindex=index+1;
54             index=Partiton(array,startindex,endindex);
55         }
56     }
57     return index;
58 }
59
60
61 int main()
62 {
63     int array[]={4,5,1,6,2,7,3,8};
64     int len=8;
65     int Index;
66     int k=4;
67     Index=FindTopK(array,0,len-1,k);
68
69     cout<<"The Top K number is: ";
70     for(int i=0;i<Index+1;i++)
71     {
72         cout<<array[i]<<" ";
73     }
74     cout<<endl;
75     system("pause");
76     return 0;
77 }