C语言实现Huffman树并计算带权路径长度

来源：互联网发布：任务计划软件编辑：程序博客网时间：2024/04/29 07:51
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#include<stdio.h>#include<stdlib.h>typedef int ElemType;typedef struct _BTreeNode {    ElemType data;    struct _BTreeNode* left;    struct _BTreeNode* right;}BTreeNode;//根据数组 a 中 n 个权值建立一棵哈夫曼树，返回树根指针BTreeNode* CreateHuffman(ElemType a[], int n){    int i, j;    BTreeNode **b, *q;    b = (BTreeNode **)malloc(n*sizeof(BTreeNode));    for (i = 0; i < n; i++) //初始化b指针数组，使每个指针元素指向a数组中对应的元素结点    {        b[i] =(BTreeNode *) malloc(sizeof(BTreeNode));        b[i]->data = a[i];        b[i]->left = b[i]->right = NULL;    }    for (i = 1; i < n; i++)//进行 n-1 次循环建立哈夫曼树    {        //k1表示森林中具有最小权值的树根结点的下标，k2为次最小的下标        int k1 = -1, k2;        for (j = 0; j < n; j++)//让k1初始指向森林中第一棵树，k2指向第二棵        {            if (b[j] != NULL && k1 == -1)            {                k1 = j;                continue;            }            if (b[j] != NULL)            {                k2 = j;                break;            }        }        for (j = k2; j < n; j++)//从当前森林中求出最小权值树和次最小        {            if (b[j] != NULL)            {                if (b[j]->data < b[k1]->data)                {                    k2 = k1;                    k1 = j;                }                else if (b[j]->data < b[k2]->data)                    k2 = j;            }        }        //由最小权值树和次最小权值树建立一棵新树，q指向树根结点        q =(BTreeNode *) malloc(sizeof(BTreeNode));        q->data = b[k1]->data + b[k2]->data;        q->left = b[k1];        q->right = b[k2];        b[k1] = q;//将指向新树的指针赋给b指针数组中k1位置        b[k2] = NULL;//k2位置为空    }    free(b); //删除动态建立的数组b    return q; //返回整个哈夫曼树的树根指针}ElemType WeightPathLength(BTreeNode* FBT, int len)//len初始为0{    if (FBT == NULL) //空树返回0        return 0;    else    {        if (FBT->left == NULL && FBT->right == NULL)//访问到叶子结点            return FBT->data * len;        else //访问到非叶子结点，进行递归调用，返回左右子树的带权路径长度之和，len递增            return WeightPathLength(FBT->left,len+1)+WeightPathLength(FBT->right,len+1);    }}//主函数void main(){    int n, i;    ElemType* a;    BTreeNode* fbt;    while(1)    {        scanf("%d", &n);        if (n > 1)            break;        else            printf("重输n值：");    }    a =(int *) malloc(n*sizeof(ElemType));       for (i = 0; i < n; i++)        scanf(" %d", &a[i]);    fbt = CreateHuffman(a, n);    printf("%d\n", WeightPathLength(fbt, 0));        }
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