哈夫曼树

该篇文章主要求解哈夫曼编码

代码示例：

#include <iostream>using namespace std;const int MaxLeng=50;//哈夫曼编码最大长度const int MaxSize=100;//最多总结点个数template <typename T>struct HTNode //哈夫曼树结点类{T data;//结点值double weight;//权值int parent;//双亲结点int lchild;//左孩子结点int rchild;//右孩子结点};struct HCode//哈夫曼编码类型{char cd[MaxLeng];//存放当前结点的哈夫曼码int start;//用cd[start..n0]存放哈夫曼码};template <typename T>class HuffmanClass//哈夫曼树类模板{int n0;//权值个数HTNode<T> ht[MaxSize];//存放哈夫曼树HCode hcd[MaxSize];//存放哈夫曼编码public:void Setvalue(T *str,double d[],int m);//设置初值void CreateHT();//构造哈夫曼树void CreateHCode();//根据哈夫曼树求哈夫曼编码void DispHCode();//输出哈夫曼编码};template <typename T>void HuffmanClass<T>::Setvalue(T *str,double d[],int m)//设置初值{int i;n0=m;for (i=0;i<m;i++){ht[i].data=str[i];ht[i].weight=d[i];}}template <typename T>void HuffmanClass<T>::CreateHT()//构造哈夫曼树{int i,k,lnode,rnode;double min1,min2;for (i=0;i<(2*n0-1);i++)//所有结点的相关域置初值-1{ht[i].parent=-1;ht[i].lchild=-1;ht[i].rchild=-1;}for (i=n0;i<(2*n0-1);i++)//构造哈夫曼树，仅求非叶子结点{min1=min2=32767.00;lnode=rnode=-1;//lnode和rnode为两个权重最小的结点位置for (k=0;k<=(i-1);k++)//在ht数组中找权值最小的两个结点if (ht[k].parent==-1)//只在尚未构造二叉树的结点中查找{if (ht[k].weight<min1){min2=min1; rnode=lnode;min1=ht[k].weight;lnode=k;}else if (ht[k].weight<min2){min2=ht[k].weight;rnode=k;}}ht[lnode].parent=i; ht[rnode].parent=i;ht[i].weight=ht[lnode].weight+ht[rnode].weight;ht[i].lchild=lnode;ht[i].rchild=rnode;//ht[i]作为双亲结点}}template <typename T>void HuffmanClass<T>::CreateHCode()//根据哈夫曼树求哈夫曼编码{int i,f,c;for (i=0;i<n0;i++)//遍历下标从0到n0-1的叶子结点{hcd[i].start=n0;c=i; f=ht[i].parent;while (f!=-1)//循环直到无双亲结点即到达树根结点{if (ht[f].lchild==c)//当前结点是双亲结点的左孩子结点{hcd[i].cd[hcd[i].start]='0';hcd[i].start--;}else//当前结点是双亲结点的右孩子结点{hcd[i].cd[hcd[i].start]='1';hcd[i].start--;}c=f; f=ht[f].parent;//再对双亲结点进行同样的操作}hcd[i].start++;//start指向哈夫曼编码最开始字符}}template <typename T>void HuffmanClass<T>::DispHCode()//输出哈夫曼编码{int i,j;for (i=0;i<n0;i++){cout << "  " << ht[i].data << ": ";for (j=hcd[i].start;j<=n0;j++)cout << hcd[i].cd[j];cout << endl;}}void main(){HuffmanClass<char> hf;int m=8;char str[]="abcdefgh";double d[]={0.07,0.19,0.02,0.06,0.32,0.03,0.21,0.10};hf.Setvalue(str,d,m);//设置初值hf.CreateHT();//建立哈夫曼树hf.CreateHCode();//建立哈夫曼编码cout << "输出哈夫曼编码如下:\n";hf.DispHCode();//输出哈夫曼编码cout << "main结束,销毁所有建立的对象\n";}