第11週実践項目1—検証アルゴリズム(4)ハフマン符号化のアルゴリズム検証

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<span style="font-family: Arial, Helvetica, sans-serif;"></span><pre name="code" class="cpp">/*Copyright (c)2015,              
All rights reserved.
    :  1-3.cbp
      :   
    :2015 11 15 
     :v1.0


    :            ,     。


    : 
    :    
*/
 
 
<span style="font-family: Arial, Helvetica, sans-serif;">    :</span>
#include <stdio.h>
#include <string.h>

#define N 50        //     
#define M 2*N-1     //      

//           
typedef struct
{
    char data;  //   
    double weight;  //  
    int parent;     //    
    int lchild;     //     
    int rchild;     //     
} HTNode;

//              
typedef struct
{
    char cd[N]; //      
    int start;
} HCode;

//      
void CreateHT(HTNode ht[],int n)
{
    int i,k,lnode,rnode;
    double min1,min2;
    for (i=0; i<2*n-1; i++)         //           -1
        ht[i].parent=ht[i].lchild=ht[i].rchild=-1;
    for (i=n; i<2*n-1; i++)         //      
    {
        min1=min2=32767;            //lnode rnode            
        lnode=rnode=-1;
        for (k=0; k<=i-1; k++)
            if (ht[k].parent==-1)   //               
            {
                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[i].weight=ht[lnode].weight+ht[rnode].weight;
        ht[i].lchild=lnode;
        ht[i].rchild=rnode;
        ht[lnode].parent=i;
        ht[rnode].parent=i;
    }
}

//       
void CreateHCode(HTNode ht[],HCode hcd[],int n)
{
    int i,f,c;
    HCode hc;
    for (i=0; i<n; i++) //            
    {
        hc.start=n;
        c=i;
        f=ht[i].parent;
        while (f!=-1)   //        
        {
            if (ht[f].lchild==c)    //       
                hc.cd[hc.start--]='0';
            else                    //       
                hc.cd[hc.start--]='1';
            c=f;
            f=ht[f].parent;
        }
        hc.start++;     //start            
        hcd[i]=hc;
    }
}

//       
void DispHCode(HTNode ht[],HCode hcd[],int n)
{
    int i,k;
    double sum=0,m=0;
    int j;
    printf("         :
"); // for (i=0; i<n; i++) { j=0; printf(" %c:\t",ht[i].data); for (k=hcd[i].start; k<=n; k++) { printf("%c",hcd[i].cd[k]); j++; } m+=ht[i].weight; sum+=ht[i].weight*j; printf("
"); } printf("
=%g
",1.0*sum/m); } int main() { int n=8,i; //n char str[]= {'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h'}; double fnum[]= {0.07,0.19,0.02,0.06,0.32,0.03,0.21,0.1}; HTNode ht[M]; HCode hcd[N]; for (i=0; i<n; i++) { ht[i].data=str[i]; ht[i].weight=fnum[i]; } printf("
"); CreateHT(ht,n); CreateHCode(ht,hcd,n); DispHCode(ht,hcd,n); printf("
"); return 0; }
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