哈夫曼编码

#include "stdio.h"#include "stdlib.h"#define N 10int A[2*N];//标志数组，用于Select函数typedef struct {char value;int weight;int parent;int lchild;int rchild;}HTNode;//HuffManTree结点typedef struct HCNode{char value;struct HCNode *next;}HCNode;//HC结点int Select(HTNode *HT,int n,int *i,int *j){int k=1;for (k=1,*i=0; k<=n; k++){if(HT[k].weight <= HT[*i].weight)if(A[k] == 0)*i=k;if(k==n)A[*i]=1;}for (k=1,*j=0; k<=n; k++){if(HT[k].weight <= HT[*j].weight)if(A[k] == 0)*j=k;if(k==n)A[*j]=1;}return 1;}HuffManHC(HTNode * HT,HCNode * HC){int i,p,q;HCNode * HC1;for (i=1; i<=N; i++){p=i;HC[i].value=HT[i].value;while(HT[p].parent != 0){q=p;p=HT[p].parent;HC1=(HCNode *)malloc(sizeof(HCNode));if(HT[p].lchild == q)HC1->value='0';else HC1->value='1';HC1->next=HC[i].next;HC[i].next=HC1;}}for (i=1; i<=N; i++){//输出HuffMan编码所对应的数组型链表printf("%c: ",HC[i].value);HC1=HC[i].next;while(HC1){printf("%c",HC1->value);HC1=HC1->next;}printf("\n");}}int main () {char v;int i,j,k;HTNode *HT;HCNode *HC;int m=2*N-1;//总节点数目HT = (HTNode *) malloc ((m+1) * sizeof(HTNode));//0号单元不用for (i=0; i<m+1; i++) {HT[i].value='^';HT[i].weight=0;HT[i].parent=0;HT[i].lchild=0;HT[i].rchild=0;}//初始化HuffManTreefor (i=1; v !='!'; i++){//输入字符，并用求对应权值,注意此程序限制叶子节点个数位N，字符常量v=getchar();for (j=1; j<=i; j++){//判断字符是否与先前输入相同if(v==HT[j].value && v!='!'){HT[j].weight += 1;//相同则权值+1i--;break;}if(i==j && v!='!'){HT[i].value=v;HT[i].weight=1;}}}for (i=0;i<m+1;i++)A[i]=0;//初始化标志数组HT[0].weight=100000;//鉴于Select函数特殊需要，避免了部分错误for(k=N+1; k<=m; k++){//建立完整HuffManTreeSelect(HT,k-1,&i,&j);//通过函数选择权值最小的两个结点,/HT为指针/HT[k].lchild=i;HT[k].rchild=j;HT[k].weight=HT[i].weight+HT[j].weight;HT[i].parent=k;HT[j].parent=k;}for (i=0; i<=m; i++)//输出数组表示法所建立的HuffManTreeprintf("%c %4d%4d%4d%4d\n",HT[i].value,HT[i].weight,HT[i].parent,HT[i].lchild,HT[i].rchild);HC=(HCNode *)malloc((N+1)*sizeof(HCNode));for (i=0;i<=N;i++)//初始化HuffMan编码数组链表HC[i].next=NULL;HuffManHC(HT,HC);getchar();j=2*N-1;v=' ';for(; v!='!'; ){v=getchar();if(v=='0')j=HT[j].lchild;else if (v=='1')j=HT[j].rchild;else if(v!='!'){printf("ENTER ERROR1\n");exit(0);}}if(j>N)printf("ENTER ERROR2\n");if(0 < j &&  <= N)printf("%c\n",HT[j].value);if(j==0)printf("ENTER ERROR3\n");return 0;}