转载：哈夫曼树的构造和哈夫曼编码（C++代码实现）

#include<stdio.h>

#define MAX 100

#define MAXVALUE 500

typedef  struct

{  

    int weight;

       int parent,lchild,rchild;

}node; /*哈夫曼树结点类型*/

 

/*-----------------------------以下部分定义哈夫曼编码存储结构-------------------------*/

typedef struct{

    int start;    //存放起始位置 

    char bits[10+1];    //存放编码位串 

}codetype;

typedef struct{

    char symbol;    //存储字符 

    codetype code;

}element;

void getMinElementLocal(node t[] ,int num , int *minLocal1 , int *minLocal2) ;

/*---------------------------------------------------------------------------------------------------*/

/*构建哈夫曼树。n为构建哈夫曼树的叶子结点个数，数组w存储每个叶子的权值，数组t存储构建好的哈夫曼树*/

void huffman(int n,int w[],node t[])

{

    int m = 0 ;

    int minLocal1 , minLocal2 ;

    int i = 0 ;

    node * nodes = NULL ;

    if(n == 0) return ;

    m = 2*n -1 ;

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

        t[i].weight = w[i] ;

        t[i].lchild = t[i].parent = t[i].rchild = -1 ;

    }

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

        t[i].weight = 0 ;

        t[i].lchild = t[i].parent = t[i].rchild = -1 ;

    }

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

        minLocal1 = minLocal2 = -2 ;

        getMinElementLocal(t , n+i , &minLocal1 , &minLocal2) ;

        t[n+i].weight = t[minLocal1].weight + t[minLocal2].weight ;

        t[n+i].lchild = minLocal1 ;

        t[n+i].rchild = minLocal2 ;

        t[minLocal1].parent = n+i ;

        t[minLocal2].parent = n+i ;    

    }

 

}

void getMinElementLocal(node t[] ,int num , int *minLocal1 , int *minLocal2){

    int i = 0 ;

    int temp1 = MAXVALUE ;

    int temp2 = MAXVALUE ;

 

    *minLocal1 = *minLocal2 = 0 ;

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

        if(t[i].weight <= temp1 && t[i].parent == -1){

            temp1 = t[i].weight ;

            *minLocal1 = i ;

        }

    }

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

        if(t[i].weight <= temp2 && t[i].parent == -1 && i != *minLocal1){

            temp2 = t[i].weight ;

            *minLocal2 = i ;

        }

    }

}

/*---------------------------------------------------------------------------------------------------*/

/*根据哈夫曼树，求哈夫曼编码表。tree存储哈夫曼树，table存储哈夫曼编码表，n为哈夫曼树叶子个数*/

void sethufcode(node tree[],element table[],int n)

 {    

    int i,j,s,f;    /* 和f分别指示tree中孩子和双亲的位置*/

       codetype c;/*时存放编码 */

    for(i=1;i<=n;i++)/*次求叶子tree[i]的编码 */

    {    

        printf("%d:",tree[i].weight);

        c.start=n+1;

                s=i;/*叶子tree[i]开始上溯 */

            while(tree[s].parent != -1)/*至上溯到树根为止 */

        {    

            f=tree[s].parent ;

            c.bits[--c.start]= (s == tree[f].lchild)?‘0‘:‘1‘;

               s=f;

             }

            for(j=c.start ;j<n+1;j++)

                      printf("%c",c.bits[j]);

             printf("/n");

             table[i].code=c;/*时编码复制到最终位置 */     

         } 

}

/*---------------------------------------------------------------------------------------------------*/

void main()

{  

    node t[100];

    int i,n,w[100];

    element m[100];

    printf("请输入结点数：");

    scanf("%d",&n);

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

    {

        printf("请输入第%d个结点权重：", i);

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

    }

    /*构造哈夫曼树*/

    huffman(n ,w , t) ;

 

    printf("序号 权重 双亲 左孩 右孩/n");  /*输出哈夫曼树*/

    for(i=1;i<(2*n);i++)

        printf("%-5d%-5d%-5d%-5d%-5d/n",i,t[i].weight,t[i].parent,t[i].lchild,t[i].rchild);

    sethufcode(t,m,n); /*构造并输出哈夫曼编码表*/

 }