排序算法之堆排序

 1 #include<iostream>
 2 using namespace std;
 3 
 4 void adjustHeap(int A[], int len,int k)
 5 {
 6     int lchild = k*2+1,rchild = lchild+1;
 7     
 8     while(rchild<len)
 9     {
10         if(A[k]>=A[lchild]&&A[k]>=A[rchild])
11         {
12             return;
13         }
14         //取出左右节点的最大值并与其父节点交换
15         if (A[lchild]>A[rchild])
16         {
17             swap(A[k],A[lchild]);
18             k = lchild;
19         }
20         else
21         {
22             swap(A[k],A[rchild]);
23             k = rchild;
24         }
25         //堆lchild和rchild重新赋值，循环
26         lchild = k*2+1;
27         rchild = lchild+1;
28     }
29     //如果只有左孩子，比较左孩子节点与父节点的值
30     if(lchild<len&&A[lchild]>A[k])
31     {
32         swap(A[lchild],A[k]);
33         return;
34     }
35 }
36 
37 void BuildMaxHeap(int A[],int len)
38 {
39     for(int i=len/2-1;i>=0;i--)
40     {
41         adjustHeap(A,len,i);
42     }
43     for(int i=0;i<8;i++)
44     {
45         cout<<"init A"<<A[i]<<endl;
46     }
47 }
48 
49 void HeapSort(int A[],int len)
50 {
51     BuildMaxHeap(A,len);
52     for(int i=len;i>1;i--)
53     {
54         //将堆顶元素与堆底元素交换
55         swap(A[i-1],A[0]);
56         adjustHeap(A,i-1,0);
57 
58 
59     }
60 }
61 void main()
62 {
63     int A[8] = {21,45,67,23,76,42,12,54};
64     HeapSort(A,8);
65     for(int i=0;i<8;i++)
66     {
67         cout<<A[i]<<endl;
68     }
69 }