最大堆与堆排序

参考《Introduce to Algorithm》

  1 #ifndef MAX_HEAP_H
  2 #define MAX_HEAP_H
  3
  4 constint MAX_SIZE = 100+ 1;
  5
  6 template<typename Type>
  7 class MaxHeap
  8 {
  9     public:
10         MaxHeap();
11         MaxHeap(Type*arr, int size);
12         //~MaxHeap();
13        
14         void travel();
15         void HeapSort();
16
17     private:
18         Type _arr[MAX_SIZE];
19         int _size;
20
21         void MaxHeapify(int startIndex);//调整堆
22        void InitBuildMaxHeap();//初始建堆
23        void swap(Type&a, Type &b);
24 };
25
26 template <typename Type>
27 MaxHeap<Type>::MaxHeap()
28 {
29     for(int i= 0; i< MAX_SIZE; i++)
30     {
31         _arr[i]= 0;
32     }
33     _size= 0;
34 }
35
36 template <typename Type>
37 MaxHeap<Type>::MaxHeap(Type*arr, int size)
38 {
39     if(size > MAX_SIZE)
40     {
41         cerr<< "larger than MAX_SIZE"<< endl;
42     }
43     for(int i= 0; i< size; i++)
44     {
45         _arr[i+1]= arr[i];
46     }
47     _size= size;
48     InitBuildMaxHeap();
49 }
50
51 template <typename Type>
52 void MaxHeap<Type>::HeapSort()
53 {
54     int tmp = _size;
55     for(int i= _size; i >=2; i--)
56     {
57         swap(_arr[1], _arr[i]);
58         _size--;
59         MaxHeapify(1);
60     }
61    
62     _size= tmp;
63    
64 }
65
66 template <typename Type>
67 void MaxHeap<Type>::InitBuildMaxHeap()
68 {
69     for(int i= _size/2; i>= 1; i--)
70     {
71         MaxHeapify(i);
72     }
73 }
74
75
76
77 template <typename Type>
78 void MaxHeap<Type>::travel()
79 {   
80     for(int i= 1; i<= _size; i++)
81         cout<< _arr[i] << "";
82
83     cout << endl;
84 }
85
86
87 template <typename Type>
88 void MaxHeap<Type>::MaxHeapify(int startIndex)
89 {
90     int maxIndex = startIndex;
91     if(2*startIndex<= _size && _arr[startIndex]< _arr[2*startIndex])
92         maxIndex= 2*startIndex;
93     if(2*startIndex+1<= _size && _arr[maxIndex] < _arr[2*startIndex+1])
94         maxIndex= 2*startIndex+1;
95
96     if(maxIndex != startIndex)
97     {
98         swap(_arr[startIndex], _arr[maxIndex]);
99         MaxHeapify(maxIndex);
100     }
101
102 }
103
104
105 template<typename Type>
106 void MaxHeap<Type>::swap(Type&a, Type &b)
107 {
108     Type t;
109     t = a;
110     a = b;
111     b = t;
112 }
113
114
115
116
117 #endif

1 #include <iostream>
2 #include "maxHeap.h"
3 usingnamespace std;
4
5 int main()
6 {
7     int arr[9]= {23,43, 74, 12,4, 69,28, 26, 32};
8     MaxHeap<int> obj(arr,9);
9     obj.travel();
10     obj.HeapSort();
11     obj.travel();
12
13     return 0;
14 }