第十一周项目1 算法验证4 哈夫曼树

#include <stdio.h>
#include <string.h>

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

//哈夫曼树的节点结构类型
typedef struct
{
    char data;  
    double weight;  
    int parent;     
    int lchild;     
    int rchild;     
} HTNode;


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

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

//实现哈夫曼编码
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++;     
        hcd[i]=hc;
    }
}


void DispHCode(HTNode ht[],HCode hcd[],int n)
{
    int i,k;
    double sum=0,m=0;
    int j;
    printf("  输出哈夫曼编码:\n"); 
    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("\n");
    }
    printf("\n  平均长度=%g\n",1.0*sum/m);
}

int main()
{
    int n=8,i;      
    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("\n");
    CreateHT(ht,n);
    CreateHCode(ht,hcd,n);
    DispHCode(ht,hcd,n);
    printf("\n");
    return 0;
}