HUFFMAN 编码

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <malloc.h>
#include <conio.h>

typedef struct {
unsigned int weight;
unsigned int parent,lchild,rchild;
} HTNode,*HuffmanTree;

typedef char **HuffmanCode;

typedef struct {
unsigned int s1;
unsigned int s2;
} MinCode;

void Error(char *message);
HuffmanCode HuffmanCoding(HuffmanTree HT,HuffmanCode HC,unsigned int *w,unsigned int n);
MinCode Select(HuffmanTree HT,unsigned int n);

void Error(char *message)
{

fprintf(stderr,"Error:%s/n",message);
exit(1);
}

HuffmanCode HuffmanCoding(HuffmanTree HT,HuffmanCode HC,unsigned int *w,unsigned int n)
{
unsigned int i,s1=0,s2=0;
HuffmanTree p;
char *cd;
unsigned int f,c,start,m;
MinCode min;
if(n<=1) Error("Code too small!");
m=2*n-1;
HT=(HuffmanTree)malloc((m+1)*sizeof(HTNode));
for(p=HT,i=0;i<=n;i++,p++,w++)
{
p->weight=*w;
p->parent=0;
p->lchild=0;
p->rchild=0;
}
for(;i<=m;i++,p++)
{
p->weight=0;
p->parent=0;
p->lchild=0;
p->rchild=0;
}
for(i=n+1;i<=m;i++)
{
min=Select(HT,i-1);
s1=min.s1;
s2=min.s2;
HT[s1].parent=i;
HT[s2].parent=i;
HT[i].lchild=s1;
HT[i].rchild=s2;
HT[i].weight=HT[s1].weight+HT[s2].weight;
}
printf("HT List:/n");
printf("Number/t/tweight/t/tparent/t/tlchild/t/trchild/n");
for(i=1;i<=m;i++)
printf("%d/t/t%d/t/t%d/t/t%d/t/t%d/n",
i,HT[i].weight,HT[i].parent,HT[i].lchild,HT[i].rchild);
HC=(HuffmanCode)malloc((n+1)*sizeof(char *));
cd=(char *)malloc(n*sizeof(char *));
cd[n-1]='/0';
for(i=1;i<=n;i++)
{
start=n-1;
for(c=i,f=HT[i].parent;f!=0;c=f,f=HT[f].parent)
if(HT[f].lchild==c) cd[--start]='0';
else cd[--start]='1';
HC[i]=(char *)malloc((n-start)*sizeof(char *));
strcpy(HC[i],&cd[start]);
}
free(cd);
return HC;
}

MinCode Select(HuffmanTree HT,unsigned int n)
{
unsigned int min,secmin;
unsigned int temp;
unsigned int i,s1,s2,tempi;
MinCode code;
s1=1;s2=1;
for(i=1;i<=n;i++)
if(HT[i].parent==0)
{
min=HT[i].weight;
s1=i;
break;
}
tempi=i++;
for(;i<=n;i++)
if(HT[i].weight<min&&HT[i].parent==0)
{
min=HT[i].weight;
s1=i;
}
for(i=tempi;i<=n;i++)
if(HT[i].parent==0&&i!=s1)
{
secmin=HT[i].weight;
s2=i;
break;
}
for(i=1;i<=n;i++)
if(HT[i].weight<secmin&&i!=s1&&HT[i].parent==0)
{
secmin=HT[i].weight;
s2=i;
}
if(s1>s2)
{
temp=s1;
s1=s2;
s2=temp;
}
code.s1=s1;
code.s2=s2;
return code;
}

void main()
{
HuffmanTree HT=NULL;
HuffmanCode HC=NULL;
unsigned int *w=NULL;
unsigned int i,n;

printf("Input n:/n");
scanf("%d",&n);
w=(unsigned int *)malloc((n+1)*sizeof(unsigned int *));
w[0]=0;
printf("Enter weight:/n");
for(i=1;i<=n;i++)
{
printf("w[%d]=",i);
scanf("%d",&w[i]);
}
HC=HuffmanCoding(HT,HC,w,n);
printf("HuffmanCode:/n");
printf("Number/t/tWeight/t/tCode/n");
for(i=1;i<=n;i++)
printf("%d/t/t%d/t/t%s/n",i,w[i],HC[i]);

}