#include<stdio.h>
#include<iostream.h>
#include<malloc.h>
#include<string.h>
#define N 50
#define M 2*N-1
typedef struct
{
char data;
int weight;
int parent;
int lchild;
int rchild;
}HTNode;
typedef struct
{
char cd[N];
int start;
}HCode;
void CreateHT(HTNode ht[],int n)
{
int i,k,lnode,rnode;
int 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[lnode].parent=i;ht[rnode].parent=i;
ht[i].weight=ht[lnode].weight+ht[rnode].weight;
ht[i].lchild=lnode;ht[i].rchild=rnode;
}
}
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;

int sum=0,m=0,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);
}
void encode(HTNode ht[],HCode hcd[],int n)
{
char bs;
int i,k;
cin>>bs;
for(i=1;i<=n;i++)
{
if (bs==ht[i].data)
for(k=hcd[i].start;k<=n;k++)
cout<<hcd[i].cd[k];

}

}
void decode(HTNode ht[],HCode hcd[],int n)
{
int t,i;
char buff[20];
t=2*n-1;
printf("请输入一个哈夫曼编码:\n");
cin>>buff;
for(i=0;i<strlen(buff);i++)
{

if(buff[i]=='0')
t=ht[t].lchild;
else
t=ht[t].rchild;
if(ht[t].lchild==-1&&ht[t].rchild==-1)
{
cout<<ht[t].data;
t=2*n-1;
}

}

}
void main()
{
int n,i;
int fnum;
HTNode ht[M];
HCode hcd[N];
printf("请想输入多少个数据？");
scanf("%d",&n);
for(i=0;i<n;i++)
{
printf("请输入第%d个的节点值\n",i+1);
cin>>ht[i].data;
printf("权值:");
cin>>ht[i].weight;
}
printf("\n");
CreateHT(ht,n);
CreateHCode(ht,hcd,n);
DispHCode(ht,hcd,n);
decode(ht,hcd,n);
}