赫尔曼算法及应用

借鉴的博客：

http://baike.sogou.com/v111784.htm

http://blog.csdn.net/cqnuztq/article/details/8919204

http://blog.csdn.net/pony_maggie/article/details/41620389

http://blog.csdn.net/JavaAlpha/article/details/4222845

实现代码：

#include <iostream> 
#define MAXVALUE 100000
using namespace std;
const int n=4;//叶子节点个数 
string l;
int size;
//构造哈夫曼树结点 
typedef struct{
   int weight;//权值 
   int parent;//父节点 
   int lchild;//左子树 
   int rchild;//右子树 
}HNodeType;

HNodeType HFMTree[2*n-1];//结点数 

//构造哈夫曼编码数组
typedef struct{
   int bit[n];
   int start;
}HCodeType;

HCodeType HFMCode[n];
//创建哈夫曼树 
void createHFMTree(HNodeType HFMTree[],int n){
   int m1,x1,m2,x2;
   int i,j;
//初始化
   for(i=0;i<2*n-1;i++){
     HFMTree[i].weight=0;
     HFMTree[i].parent=-1;
     HFMTree[i].lchild=-1;
     HFMTree[i].rchild=-1;
   }
   cout<<"*******************哈夫曼树字符串最优转码程序***********************"<<endl; 
   cout<<"请输入一个字符串：(只含有A，B，C，D四种字符,输入回车结束)"<<endl; 
   cin>>l;
   string str(l);
   size=str.size();    
   for(int i=0;i<size;++i){   
     if(str.at(i)=='A')HFMTree[0].weight++;
     else if(str.at(i)=='B')HFMTree[1].weight++;
     else if(str.at(i)=='C')HFMTree[2].weight++;
     else if(str.at(i)=='D')HFMTree[3].weight++;
     else{ 
       cout<<"输入有误!"<<endl;
       break;
     }
 49   }

  for(i=0;i<n-1;i++){
    x1=x2=MAXVALUE;
    m1=m2=0;
    for(j=0;j<n+i;j++){
      if(HFMTree[j].parent==-1&&HFMTree[j].weight<x1){
        x2=x1;
        m2=m1;
        x1=HFMTree[j].weight;
        m1=j;
      }
      else if(HFMTree[j].parent==-1&&HFMTree[j].weight<x2){
        x2=HFMTree[j].weight;
        m2=j;
      }
   }
   HFMTree[m1].parent=n+i;HFMTree[m2].parent=n+i;
   HFMTree[n+i].weight=HFMTree[m1].weight+HFMTree[m2].weight;
   HFMTree[n+i].lchild=m1;
   HFMTree[n+i].rchild=m2;
   }
}
//转化编码 
void createHFMCode(HNodeType HFMTree[],HCodeType HFMCode[]){
   HCodeType cd;
   int i,j,c,p;
for(i=0;i<n;i++){
   cd.start=n-1;
   c=i;
   p=HFMTree[c].parent;
   while(p!=-1)
   {
    if(HFMTree[p].lchild==c)cd.bit[cd.start]=0;
    else cd.bit[cd.start]=1;
    cd.start--;
    c=p;
    p=HFMTree[c].parent;
   }
   for(j=cd.start+1;j<n;j++)
    HFMCode[i].bit[j]=cd.bit[j];
   HFMCode[i].start=cd.start+1;
}
}
//主函数 
int main()
{
   int i,j;
//创建树 
   createHFMTree(HFMTree,n);
//转码 
   createHFMCode(HFMTree,HFMCode);
   cout<<endl;
   int k=65;
for(i=0;i<n;i++)
{
   cout<<(char)k<<"的编码：";
   for(j=HFMCode[i].start;j<=n-1;j++)
   {
    cout<<HFMCode[i].bit[j];
   }
   k++;
   cout<<endl;
}
   cout<<"转码后的字符串为："<<endl;
   string str(l);
   size=str.size();    
   for(int i=0;i<size;++i){   
   if(str.at(i)=='A'){
   for(j=HFMCode[0].start;j<=n-1;j++)
     cout<<HFMCode[0].bit[j];
   }
   else if(str.at(i)=='B'){
   for(j=HFMCode[1].start;j<=n-1;j++)
     cout<<HFMCode[1].bit[j];
   }
   else if(str.at(i)=='C'){
   for(j=HFMCode[2].start;j<=n-1;j++)
     cout<<HFMCode[2].bit[j];
   }
   else if(str.at(i)=='D'){
   for(j=HFMCode[3].start;j<=n-1;j++)
     cout<<HFMCode[3].bit[j];
   }
   else{ 
     cout<<"输入有误!"<<endl;
   break;
   }
}
   return 0;
}