数据结构与算法李春葆系列之哈夫曼树

#include<stdio.h>
#include<string.h>
#define N 15      
typedef struct
{
	char data[4];
	double weight;
	int parent;
	int lchild;
	int rchild;
}HTNode;
typedef struct
{
	char cd[N];
	int start;
}HCode;
void CreatHCode(HTNode ht[],HCode hcd[],int n0)
{
	int i,f,c;
	HCode hc;
	for(i=0;i<n0;i++)
	{
		hc.start=n0;
		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 CreatHT(HTNode ht[],int n0)
{
	int i;
	int k;
	int lnode;
	int rnode;
	double min1;
	double min2;
	for(i=0;i<2*n0-1;i++)
	{
		ht[i].parent=ht[i].lchild=ht[i].rchild=-1;
	}
	for(i=n0;i<=2*n0-2;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;
	}
}
void Show(HTNode ht[],HCode hcd[],int n)
{
    int i;
    int k;
    int sum=0;
    int sumWeight=0;
    int j;
    printf(" 输出哈夫曼编码:
");
    for(i=0;i<n;i++)
    {
        j=0;
        printf("%s: ",ht[i].data);
        for(k=hcd[i].start;k<=n;k++)
        {
            printf("%c",hcd[i].cd[k]);
            j++;
        }
        sum+=ht[i].weight;
        sumWeight+=ht[i].weight*j;
        printf("
");
    }
    printf(" 平均查找长度=%1.3f",1.000*sumWeight/sum);
}
void Giv(HTNode a[],double b[],char *s[])
{
	for(int i=0;i<15;i++)
    {
        strcpy(a[i].data,s[i]);
        a[i].weight=b[i];
    }
	
}
int main()
{
    HTNode lev[15];
    char *str[15]={"The","of","a","to","and","in","that","he","is","at","on","for","His","are", "be"};
    double weight[15]={1192,677,541,518,462,450,242,195,190,181,174,157,138,124,123};
    for(int i=0;i<15;i++)
    {
        strcpy(lev[i].data,str[i]);
        lev[i].weight=weight[i];
    }
    CreatHT(lev,15);
    HCode levW[15];
    CreatHCode(lev,levW,15); 
    Show(lev,levW,15); 
    return 0;
}