第十周 项目5 - 哈曼树

#include <stdio.h>
#include <string.h>#define N 50        //叶子结点数
#define M 2*N-1     //树中结点总数//哈夫曼树的节点结构类型
typedef struct
{char data;  //结点值double weight;  //权重int parent;     //双亲结点int lchild;     //左孩子结点int rchild;     //右孩子结点
} HTNode;//每个节点哈夫曼编码的结构类型
typedef struct
{char cd[N]; //存放哈夫曼码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++)         //所有结点的相关域置初值-1ht[i].parent=ht[i].lchild=ht[i].rchild=-1;for (i=n; i<2*n-1; i++)         //构造哈夫曼树{min1=min2=32767;            //lnode和rnode为最小权重的两个结点位置lnode=rnode=-1;for (k=0; k<=i-1; k++)if (ht[k].parent==-1)   //只在尚未构造二叉树的结点中查找{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++) //根据哈夫曼树求哈夫曼编码{hc.start=n;c=i;f=ht[i].parent;while (f!=-1)   //循序直到树根结点{if (ht[f].lchild==c)    //处理左孩子结点hc.cd[hc.start--]='0';else                    //处理右孩子结点hc.cd[hc.start--]='1';c=f;f=ht[f].parent;}hc.start++;     //start指向哈夫曼编码最开始字符hcd[i]=hc;}
}//输出哈夫曼编码
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"); //输出哈夫曼编码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;      //n表示初始字符串的个数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;
}