一天一点数据结构+算法：复习堆的知识

这个代码还是有些问题，应该出在了堆头文件的保护#ifdef上。

 

大顶堆：

  1 #ifdef _MAXHEAP_H_
  2 #define _MAXHEAP_H_
  3 
  4 template <class T>
  5 class MaxHeap
  6 {
  7 
  8 public:
  9     MaxHeap(int mx = 10);
 10     virtual ~MaxHeap();
 11 
 12     bool IsEmpty();
 13     void Push(const T&);
 14     void Pop();
 15     const T& Top() const;
 16 
 17 private:
 18     T* heapArray;
 19     int maxSize;
 20     int currentSize;
 21 
 22     void trickleUp(int index);
 23     void trickleDown(int index);
 24 
 25 };
 26 
 27 
 28 template <class T>
 29 MaxHeap<T>::MaxHeap(int mx = 10)
 30 {
 31 
 32     if(mx<1) throw "max size must be >=1";
 33     maxSize = mx;
 34     currentSize = 0;
 35     heapArray = new T[maxSize];
 36 }
 37 
 38 template <class T>
 39 MaxHeap<T>::~MaxHeap()
 40 {
 41 
 42     delete[] heapArray;
 43 }
 44 
 45 template <class T>
 46 bool MaxHeap<T>::IsEmpty()
 47 {
 48 
 49     return currentSize == 0;
 50 }
 51 
 52 template <class T>
 53 void MasHeap<T>::Push(const T& e)
 54 {
 55 
 56     if(currentSize == maxSize) throw "MaxHeap is full.";
 57     
 58     heapArray[currentSize] = e;
 59     trickleUp(currentSize++);
 60     
 61 }
 62 
 63 template<class T>
 64 void MaxHeap<T>::trickleUp(int index)
 65 {
 66     int parent = (index-1)/2;
 67     T bottom = heapArray[index];//用临时变量先保存
 68     while(index > 0 && heapArray[parent] < bottom)
 69     {
 70     
 71         heapArray[index] = heapArray[parent];
 72         index = parent;
 73         parent = (parent - 1) /2 ;
 74 
 75     }
 76     heapArray[index] = bottom;
 77 
 78 
 79 }
 80 
 81 template<class T>
 82 const T& MaxHeap<T>::Top() const
 83 {
 84 
 85     return heapArray[0];
 86 }
 87 
 88 
 89 template <class T>
 90 void MaxHeap<T>::Pop()
 91 {
 92     //删除根节点，把最后一个节点拿过来。currentSize指向最后一个空位，只有减1之后才会向前找到真正的最后一个
 93     heapArray[0] = heapArray[--currentSize]; 
 94     trickleDown(0);
 95 }
 96 
 97 
 98 
 99 template <class T>
100 void MaxHeap<T>::trickleDown(int index)
101 {
102     int largerChild;
103     T top = heapArray[index];//临时的根
104 
105     //每次都是删除根节点，currentSize到最后一层的上一层
106     while(index < currentSize/2)
107     {
108     //计算节点左儿子和右儿子的序号
109     int leftChild = 2 * index + 1;
110     int rightChild = leftChild + 1;
111     if(rightChild < currentSize && heapArray[leftChild] < heapArray[rightChild])
112         largerChild = rightChild;
113     else
114         largerChild = leftChild;
115 
116     if(top >= heapArray[largerChild])
117         break;
118     else
119         //把儿子上移
120         heapArray[index] = heapArray[largerChild];
121         index= largerChild;
122 
123     }
124 
125     heapArray[index] = top;//临时的根渗透在index放下
126 }
127 
128 #endif

 

posted @ 2013-01-12 23:55  uniquews  阅读(335)  评论(0)  编辑  收藏  举报