Huffman树的实现

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// HuffmanTree.h: interface for the HuffmanTree class.
//
//////////////////////////////////////////////////////////////////////

#if !defined(AFX_HUFFMANTREE_H__E2FE6C12_C0A9_4483_AF1B_9623F1FD0EF8__INCLUDED_)
#define AFX_HUFFMANTREE_H__E2FE6C12_C0A9_4483_AF1B_9623F1FD0EF8__INCLUDED_

#if _MSC_VER > 1000
#pragma once
#endif // _MSC_VER > 1000

#include "HuffmanTreeNode.h"
#include "MinHeap.h"

template <class T>
class HuffmanTree
{
private:
HuffmanTreeNode<T>* root; //Huffman树的树根
//把ht1和ht2为根的Huffman子树合并成一棵以parent为根的二叉树
void MergeTree(HuffmanTreeNode<T> &ht1,HuffmanTreeNode<T> &ht2, HuffmanTreeNode<T>* parent);
public:
//构造Huffman树，weight是存储权值的数组，n是数组长度
HuffmanTree(T weight[],int n);
//删除Huffman树或其子树
void DeleteTree(HuffmanTreeNode<T>* root);
virtual ~HuffmanTree(); //析构函数
};

template <class T>
void HuffmanTree<T>::MergeTree(HuffmanTreeNode<T> &ht1,HuffmanTreeNode<T> &ht2, HuffmanTreeNode<T>* parent)
{
parent->left=&ht1;
parent->right=&ht2;
parent->element=ht1.element+ht2.element;
parent->parent=NULL;
ht1.parent=ht2.parent=parent;
}

template <class T>
HuffmanTree<T>::HuffmanTree(T weight[],int n)
{
MinHeap<HuffmanTreeNode<T>> heap(n);   //定义最小值堆
HuffmanTreeNode<T> *parent,&firstchild,&secondchild;
HuffmanTreeNode<T>* NodeList=new HuffmanTreeNode<T>[n];
for(int i=0;i<n;i++)       //初始化
{
  NodeList[i].element=weight[i];
  NodeList[i].parent=NodeList[i].left=NodeList[i].right=NULL;
  heap.Insert(NodeList[i]);     //向堆中添加元素
}

for(i=0;i<n-1;i++)
//通过n-1次合并建立Huffman树
{
  parent=new HuffmanTreeNode<T>;
  firstchild=heap.RemoveMin();    //选择权值最小的结点
  secondchild=heap.RemoveMin();    //选择权值次小的结点
  MergeTree(firstchild,secondchild,parent); //合并权值最小的两棵树
  heap.Insert(*parent);      //把parent插入到堆中去
  root=parent;        //建立根结点
}
delete []NodeList;
}

template <class T>
void HuffmanTree<T>::DeleteTree(HuffmanTreeNode<T>* root)
{
if(root)
{
  DeleteTree(root->left);
  DeleteTree(root->right);
  delete root;
}
}

template <class T>
virtual HuffmanTree<T>::~HuffmanTree()
{
DeleteTree(root);
}

#endif // !defined(AFX_HUFFMANTREE_H__E2FE6C12_C0A9_4483_AF1B_9623F1FD0EF8__INCLUDED_)