赫尔曼算法及应用

  1 #include <iostream> 
  2 #define MAXVALUE 100000
  3 using namespace std;
  4 const int n=4;//叶子节点个数 
  5 string l;
  6 int size;
  7 //构造哈夫曼树结点 
  8 typedef struct{
  9    int weight;//权值 
 10    int parent;//父节点 
 11    int lchild;//左子树 
 12    int rchild;//右子树 
 13 }HNodeType;
 14 
 15 HNodeType HFMTree[2*n-1];//结点数 
 16 
 17 //构造哈夫曼编码数组
 18 typedef struct{
 19    int bit[n];
 20    int start;
 21 }HCodeType;
 22 
 23 HCodeType HFMCode[n];
 24 //创建哈夫曼树 
 25 void createHFMTree(HNodeType HFMTree[],int n){
 26    int m1,x1,m2,x2;
 27    int i,j;
 28 //初始化
 29    for(i=0;i<2*n-1;i++){
 30      HFMTree[i].weight=0;
 31      HFMTree[i].parent=-1;
 32      HFMTree[i].lchild=-1;
 33      HFMTree[i].rchild=-1;
 34    }
 35    cout<<"*******************哈夫曼树字符串最优转码程序***********************"<<endl; 
 36    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; 
 37    cin>>l;
 38    string str(l);
 39    size=str.size();    
 40    for(int i=0;i<size;++i){   
 41      if(str.at(i)==‘A‘)HFMTree[0].weight++;
 42      else if(str.at(i)==‘B‘)HFMTree[1].weight++;
 43      else if(str.at(i)==‘C‘)HFMTree[2].weight++;
 44      else if(str.at(i)==‘D‘)HFMTree[3].weight++;
 45      else{ 
 46        cout<<"输入有误!"<<endl;
 47        break;
 48      }
 49   }
 50 
 51   for(i=0;i<n-1;i++){
 52     x1=x2=MAXVALUE;
 53     m1=m2=0;
 54     for(j=0;j<n+i;j++){
 55       if(HFMTree[j].parent==-1&&HFMTree[j].weight<x1){
 56         x2=x1;
 57         m2=m1;
 58         x1=HFMTree[j].weight;
 59         m1=j;
 60       }
 61       else if(HFMTree[j].parent==-1&&HFMTree[j].weight<x2){
 62         x2=HFMTree[j].weight;
 63         m2=j;
 64       }
 65    }
 66    HFMTree[m1].parent=n+i;HFMTree[m2].parent=n+i;
 67    HFMTree[n+i].weight=HFMTree[m1].weight+HFMTree[m2].weight;
 68    HFMTree[n+i].lchild=m1;
 69    HFMTree[n+i].rchild=m2;
 70    }
 71 }
 72 //转化编码 
 73 void createHFMCode(HNodeType HFMTree[],HCodeType HFMCode[]){
 74    HCodeType cd;
 75    int i,j,c,p;
 76 for(i=0;i<n;i++){
 77    cd.start=n-1;
 78    c=i;
 79    p=HFMTree[c].parent;
 80    while(p!=-1)
 81    {
 82     if(HFMTree[p].lchild==c)cd.bit[cd.start]=0;
 83     else cd.bit[cd.start]=1;
 84     cd.start--;
 85     c=p;
 86     p=HFMTree[c].parent;
 87    }
 88    for(j=cd.start+1;j<n;j++)
 89     HFMCode[i].bit[j]=cd.bit[j];
 90    HFMCode[i].start=cd.start+1;
 91 }
 92 }
 93 //主函数 
 94 int main()
 95 {
 96    int i,j;
 97 //创建树 
 98    createHFMTree(HFMTree,n);
 99 //转码 
100    createHFMCode(HFMTree,HFMCode);
101    cout<<endl;
102    int k=65;
103 for(i=0;i<n;i++)
104 {
105    cout<<(char)k<<"的编码：";
106    for(j=HFMCode[i].start;j<=n-1;j++)
107    {
108     cout<<HFMCode[i].bit[j];
109    }
110    k++;
111    cout<<endl;
112 }
113    cout<<"转码后的字符串为："<<endl;
114    string str(l);
115    size=str.size();    
116    for(int i=0;i<size;++i){   
117    if(str.at(i)==‘A‘){
118    for(j=HFMCode[0].start;j<=n-1;j++)
119      cout<<HFMCode[0].bit[j];
120    }
121    else if(str.at(i)==‘B‘){
122    for(j=HFMCode[1].start;j<=n-1;j++)
123      cout<<HFMCode[1].bit[j];
124    }
125    else if(str.at(i)==‘C‘){
126    for(j=HFMCode[2].start;j<=n-1;j++)
127      cout<<HFMCode[2].bit[j];
128    }
129    else if(str.at(i)==‘D‘){
130    for(j=HFMCode[3].start;j<=n-1;j++)
131      cout<<HFMCode[3].bit[j];
132    }
133    else{ 
134      cout<<"输入有误!"<<endl;
135    break;
136    }
137 }
138    return 0;
139 }