#define INT_MAX 10000
#define ENCODING_LENGTH 1000
#include "stdio.h"
#include "string.h"
#include "malloc.h"
typedef enum{none,left_child,right_child} Which;//标记是左孩子还是右孩子
typedef char Elemtype;
typedef struct TNode{
Elemtype letter;
int weight;
int parent;
Which sigh;
char *code;
}HTNode,*HuffmanTree;
int n;
char coding[50];//储存代码
char str[ENCODING_LENGTH];//保存要翻译的句子
void InitTreeNode(HuffmanTree &HT){//初始前N个结点,后M-N个结点置空
int i;int w;char c;
int m=2*n-1;
HuffmanTree p;
HT=(HuffmanTree)malloc((m)*sizeof(HTNode));
printf("input %d database letter and weight",n);
p=HT;
getchar();
for (i=1;i<=n;i++){
scanf("%c%d",&c,&w);
p->code='\0';
p->letter=c;
p->parent=0;
p->sigh=none;
p->weight=w;
p++;
getchar();
}
for (;i<=m;i++,p++){
p->code='\0';
p->letter=' ';
p->parent=0;
p->sigh=none;
p->weight=0;
}
}//INITTREENODE
void Select(HuffmanTree HT,int end,int *s1,int *s2){//在0~END之间,找出最小和次小的两个结点序号,返回S1,S2
int i;
int min1=INT_MAX;
int min2;
for (i=0;i<=end;i++){//找最小的结点序号
if (HT[i].parent==0&&HT[i].weight<min1){
*s1=i;
min1=HT[i].weight;
}
}
min2=INT_MAX;
for(i=0;i<=end;i++){//找次小结点的序号
if (HT[i].parent==0&&(*s1!=i)&&min2>HT[i].weight){
*s2=i;
min2=HT[i].weight;
}
}
}
void HuffmanTreeCreat(HuffmanTree &HT){//建立HUFFMAN树
int i;int m=2*n-1;
int s1,s2;
for(i=n;i<m;i++){
Select(HT,i-1,&s1,&s2);
HT[s1].parent=i;
HT[s2].parent=i;
HT[s1].sigh=left_child;
HT[s2].sigh=right_child;
HT[i].weight=HT[s1].weight+HT[s2].weight;
}
}
void HuffmanTreeCode(HuffmanTree HT){//HUFFMAN译码
int i;
char *temp;
temp=(char *)malloc(n*sizeof(char));
temp[n-1]='\0';
int p;int s;
for (i=0;i<n;i++){
p=i;
s=n-1;
while (HT[p].parent!=0){//从结点回溯,左孩子为0,右孩子为1
if (HT[p].sigh==left_child)
temp[--s]='0';
else if (HT[p].sigh==right_child)
temp[--s]='1';
p=HT[p].parent;
}
HT[i].code=(char *)malloc((n-s)*sizeof(char));//分配结点码长度的内存空间
strcpy(HT[i].code,temp+s);
printf("%s\n",HT[i].code);
}
}
void GetCodingSen(char *sencence){//输入要编码的句子
int l;
gets(sencence);
l=strlen(sencence);
sencence[l]='\0';
}
void HuffmanTreeEncoding(char sen[],HuffmanTree HT){//将句子进行编码
int i=0;int j;
while(sen[i]!='\0'){
for(j=0;j<n;j++){
if (HT[j].letter==sen[i]) //字母吻合则用代码取代
{strcat(coding,HT[j].code);
break;
}
}
i++;
if (sen[i]==32) i++;
}
printf("\n%s",coding);
}
void HuffmanTreeDecoding(HuffmanTree HT,char code[]){//HUFFMAN译码过程,将代码翻译为句子
char sen[100];
char temp[50];
char voidstr[]=" ";
int i;int j;
int t=0;int s=0;
for(i=0;i<strlen(code);i++){
temp[t++]=code[i];
for(j=0;j<n;j++){
if (strcmp(HT[j].code,temp)==0){//代码段吻合
sen[s]=HT[j].letter;s++;
strcpy(temp,voidstr);//将TEMP置空
t=0;
break;
}
}
}
printf("\n%s",sen);
}
void main(){
HTNode hnode;
HuffmanTree huff;
huff=&hnode;
printf("input the letter for coding number\n");
scanf("%d",&n);
InitTreeNode(huff);
HuffmanTreeCreat(huff);
HuffmanTreeCode(huff);
GetCodingSen(str);
HuffmanTreeEncoding(str,huff);
HuffmanTreeDecoding(huff,coding);
}
