C语言数据结构之哈夫曼树及哈夫曼编码的实现

代码清单如下：

 #pragma once
 #include<stdio.h>
 #include"stdlib.h"
 #include <string.h>

 typedef int ElemType1;

 struct BTreeNode
 {
     ElemType1 data;
     struct BTreeNode* left;
     struct BTreeNode* right;
 };
 //遍历哈夫曼树
 void PrintBTree_int(struct BTreeNode* BT)
 {
     if (BT != NULL)
     {
         printf("%d", BT->data);
         if (BT->left != NULL || BT->right != NULL)
         {
             printf(" ( ");
             PrintBTree_int(BT->left); //输出左子树
             if (BT->right != NULL)
                 printf(" , ");
             PrintBTree_int(BT->right); //输出右子树
             printf(" ) ");
         }
     }
 }

 //创建哈夫曼树
 struct BTreeNode* CreateHuffman(ElemType1 a[], int n)
 {
     int i, j;
     struct BTreeNode **b, *q;
     b = (BTreeNode **)malloc(n * sizeof(struct BTreeNode));
     for (i = ; i < n; i++)                          //动态内存分配
     {
         b[i] = (BTreeNode *)malloc(sizeof(struct BTreeNode));
         b[i]->data = a[i];
         b[i]->left = b[i]->right = NULL;
     }
     for (i = ; i < n; i++)
     {
         //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 = -, k2;
         for (j = ; 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 == -)
             {
                 k1 = j;
                 continue;
             }
             if (b[j] != NULL)
             {
                 k2 = j;
                 break;
             }
         }
         for (j = k2; j < n; j++)                 //构造最优解
         {
             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;
             }
         }
         q = (BTreeNode *)malloc(sizeof(struct BTreeNode));
         q->data = b[k1]->data + b[k2]->data;
         q->left = b[k1];
         q->right = b[k2];

         b[k1] = q;
         b[k2] = NULL;
     }
     free(b);
     return q;
 }
 //计算带权路径
 ElemType WeightPathLength(struct BTreeNode* FBT, int len)//len初始为0
 {
     if (FBT == NULL) //空树返回0
         return ;
     else
     {
         if (FBT->left == NULL && FBT->right == NULL)
             return FBT->data * len;
         else
             return WeightPathLength(FBT->left, len + ) + WeightPathLength(FBT->right, len + );
     }
 }

 //构造哈夫曼编码
 void HuffManCoding(struct BTreeNode* FBT, int len)
 {
     static int a[];
     if (FBT != NULL)
     {
         if (FBT->left == NULL && FBT->right == NULL)
         {
             int i;
             printf("结点的值为%d的编码：", FBT->data);
             for (i = ; i < len; i++)
                 printf("%d", a[i]);
             printf("\n");
         }
         else
         {
             a[len] = ;
             HuffManCoding(FBT->left, len + );
             a[len] = ;
             HuffManCoding(FBT->right, len + );
         }
     }
 }