代码

#include<iostream>
#include<string.h>
#include<stdlib.h>
using namespace std;
typedef struct 
{
    int weight;
    int parent, lchild, rchild;
}HTNode, *HuffmanTree;//动态数组，元素为HTNode
typedef char** HuffmanCode;
//编码表，每一个元素都是一个编码，即char*方式存储的字符串
//初始化权重数组
void Init_Weight(int **w, int n){
    while(!(*w=(int*)malloc((n+1)*sizeof(int))));
}
//创建权值数组
void Create_Weight(int n, int *w){
    int i, data;
    for(int i = 1;i <= n;i++){
        cin>>data;
        w[i] = data;
    }
}
//初始化哈夫曼树
void Init_HuffmanTree(HuffmanTree *HT, int *w, int n){
    int i;
    int m = 2*n-1;
    HTNode *p;
    while(!((*Ht)=(HTNode*)malloc(sizeof(HTNode)*(m+1))));
    for(p = (*HT)+1, i = 1;i <= n;i++,p++){
        p->weight = w[i];
        p->parent = 0;
        p->lchild = 0;
        p->rchild = 0;
    }
    for(;i <= m;i++,p++){
        p->lchild = 0;
        p->rchild = 0;
        p->parent = 0;
        p->weight = 0;
    }
}
//利用选择排序，循环一次即可得到最小的两个值
//在HT中选择parent为0，且权重最小的两个节点，返回他们的下标s1和s2
void Select(HuffmanTree HT, int i, int *s1, int *s2){
    int mi1 = 0. mi2 = 0;
    int j = 1;
    for(;j <= i;j++){
        if(HT[j].parent == 0){
            if(mi1==0){*s1 = j; mi1++; continue;}
            if(mi2==0){*s2 = j; mi2++; continue;}
            if(HT[*s1].weight > HT[*s2].weight&&mi1 == 1&&mi2 == 1){
                int vim = *s1, *s1 = *s2, *s2 = vim;
            }
            if(HT[j].weight < HT[*s1].weight){
                *s2 = *s1, *s1 = j;
                continue;
            }
            if(HT[j].weight < HT[*s2].weight){
                *s2 = j;
            }
        }
    }
    if(*s1 > *s2){int vim = *s1;*s1 = *s2;*s2 = vim;}
}
//创建哈夫曼树
void Create_HuffmanTree(HuffmanTree HT, int n){
    int i = n+1;
    for(;i <= n*2-1;i++){
        int s1 = 0, s2 = 0;
        Select(HT,i-1,&s1,&s2);
        HT[i].lchild = s1, HT[i].rchild = s2;
        HT[i].weight = HT[s1].weight + HT[s2].weight;
        HT[s1].parent = i, HT[s2].parent = i;
    }
}
//初始化哈夫曼编码表
void Init_HuffmenCode(HuffmanTree *HC, int n){
    while(!((*HC)=(HuffmanCode)malloc((n+1)*sizeof(char*))));
}
void GetHuffmanCode(HuffmanCode HC, HuffmanTree HT, int n){
    char ch[n];
    ch[n-1] = '\0';
    for(int i = 1;i <= n;i++){
        int st = n-2, f = HT[i].parent, c = i;
        while(f!=0){
            --st;
            if(HT[f].lchild==c)ch[st] = '0';
            else ch[st] = '1';
            c = f;
            f = HT[f].parent;
        }
        HC[i] = new char[n-st];
        strcpy(HC[i], &ch[st]);
    }
}
//打印哈夫曼编码
void PrintCode(HuffmanCode HC, int n){
    for(int i = 1;i <= n;i++){
        cout<<HC[i];
    }
}
//释放空间
void Destroy(HuffmanTree *HT, HuffmanCode *HC){
    free(*HC);
    free(*HT);
}
int main(){
    HuffmanCode HC;
    HuffmanTree HT;
    int *w, n;
    cin>>n;
    //初始化权重数组
    Init_Weight(&w, n);
    //创建权值数组
    Create_Weight(n, w);
    //初始化哈夫曼树
    Init_HuffmanTree(&HT, w, n);
    //创建哈夫曼树
    Create_HuffmanTree(HT, n);
    //初始化哈夫曼编码表
    Init_HuffmenCode(&HC, n);
    //求哈夫曼编码
    GetHuffmanCode(HC, HT, n);
    //打印哈夫曼编码表
    PrintCoder(HC,n);
    //释放空间
    Destroy(&HT,&HC);
    return 0;
}