int m,s1,s2;

typedef struct {

unsigned int weight;

unsigned int parent,lchild,rchild;

}HTNode,*HuffmanTree;

typedef char *HuffmanCode;

void Select(HuffmanTree HT,int n) {

int i,j;

for(i = 1;i <= n;i++)

if(!HT[i].parent){s1 = i;break;}

for(j = i+1;j <= n;j++)

if(!HT[j].parent){s2 = j;break;}

for(i = 1;i <= n;i++)

if((HT[s1].weight>HT[i].weight)&&(!HT[i].parent)&&(s2!=i))s1=i;

for(j = 1;j <= n;j++)

if((HT[s2].weight>HT[j].weight)&&(!HT[j].parent)&&(s1!=j))s2=j;

}

void HuffmanCoding(HuffmanTree &HT, HuffmanCode HC[], int *w, int n) {

int i, j;

char *cd;

int p;

int cdlen;

if (n<=1) return;

m = 2 * n - 1;

HT = (HuffmanTree)malloc((m+1) * sizeof(HTNode));

for (i=1; i<=n; i++) {

HT[i].weight=w[i-1];

HT[i].parent=0;

HT[i].lchild=0;

HT[i].rchild=0;

}

for (i=n+1; i<=m; i++) {

HT[i].weight=0;

HT[i].parent=0;

HT[i].lchild=0;

HT[i].rchild=0;

}

puts("\n哈夫曼树的构造过程如下所示：");

printf("HT初态:\n 结点 weight parent lchild rchild");

for (i=1; i<=m; i++)

printf("\n%4d%8d%8d%8d%8d",i,HT[i].weight,

HT[i].parent,HT[i].lchild, HT[i].rchild);

printf(" 按任意键，继续 ...");

getchar();

for (i=n+1; i<=m; i++) {

Select(HT, i-1);

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("\nselect: s1=%d s2=%d\n", s1, s2);

printf(" 结点 weight parent lchild rchild");

for (j=1; j<=i; j++)

printf("\n%4d%8d%8d%8d%8d",j,HT[j].weight,

HT[j].parent,HT[j].lchild, HT[j].rchild);

printf(" 按任意键，继续 ...");

getchar(); }

cd = (char *)malloc(n*sizeof(char));

p = m; cdlen = 0;

for (i=1; i<=m; ++i)

HT[i].weight = 0;

while (p) {

if (HT[p].weight==0) {

HT[p].weight = 1;

if (HT[p].lchild != 0) { p = HT[p].lchild; cd[cdlen++] ='0'; }

else if (HT[p].rchild == 0)

{ HC[p] = (char *)malloc((cdlen+1) * sizeof(char));

cd[cdlen] ='\0'; strcpy(HC[p], cd); }

}

else if (HT[p].weight==1)

{ HT[p].weight = 2;

if (HT[p].rchild != 0) { p = HT[p].rchild; cd[cdlen++] ='1'; }

} else { // HT[p].weight==2，HT[p].weight = 0; p = HT[p].parent; --cdlen; }

}

}

void main() {

HuffmanTree HT;HuffmanCode *HC;int *w,n,i;

puts("输入结点数:");

scanf("%d",&n);

HC = (HuffmanCode *)malloc(n*sizeof(HuffmanCode));

w = (int *)malloc(n*sizeof(int));

printf("输入%d个结点的权值\n",n);

for(i = 0;i < n;i++)

scanf("%d",&w[i]);

HuffmanCoding(HT,HC,w,n);

puts("\n各结点的哈夫曼编码:");

for(i = 1;i <= n;i++)

printf("%2d(%4d):%s\n",i,w[i-1],HC[i]);

getchar(); }