赫夫曼编码

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ACM模版

赫夫曼编码

main

main.cpp

#include <iostream>#include "huffman.hpp"int main(int argc, const char * argv[]){    //  源码    char S[] = "I love Golden Dream!";//    char S[] = "I love FishC.com!";    //  压缩码    char s[] = "01101101001111111001011100111111110000001010010110010011101101000100110101";//    char s[] = "100011001110010000101011010010100000101011111011111101100101101110";    //  构建赫夫曼树    htTree *codeTree = buildTree(S);    //  构建变长前缀码表    hlTable *codeTable = buildTable(codeTree);    //  压缩    encode(codeTable, S);    //  解压    decode(codeTree, s);    return 0;}

queue

queue.hpp

#ifndef queue_hpp#define queue_hpp#include <stdio.h>#include "huffman.hpp"#define TYPE    htNode *#define MAX_SZ  256typedef struct _pQueueNode  //  队列结点{    TYPE val;    unsigned int priority;    struct _pQueueNode *next;}pQueueNode;typedef struct _pQueue      //  队列{    unsigned int size;    pQueueNode *first;}pQueue;void initPQueue(pQueue **queue);                                    //  初始化队列void addPQueue(pQueue **queue, TYPE val, unsigned int priority);    //  插入队列头结点TYPE getPQueue(pQueue **queue);                                     //  获取队列头结点#endif /* queue_hpp */

queue.cpp

#include "queue.hpp"#include <stdlib.h>//  初始化队列void initPQueue(pQueue **queue){    (*queue) = (pQueue *)malloc(sizeof(pQueue));    (*queue)->first = NULL;    (*queue)->size = 0;    return ;}//  将出现的字符逐个插入队列，并维护出现次数是从小到大void addPQueue(pQueue **queue, TYPE val, unsigned int priority){    if ((*queue)->size == MAX_SZ)    {        printf("\nQueue is full.\n");        return ;    }    pQueueNode *aux = (pQueueNode *)malloc(sizeof(pQueueNode));    aux->priority = priority;    aux->val = val;    if ((*queue)->size == 0 || (*queue)->first == NULL)    {        aux->next = NULL;        (*queue)->first = aux;        (*queue)->size = 1;        return ;    }    else    {        //  小于头则插入头        if (priority <= (*queue)->first->priority)        {            aux->next = (*queue)->first;            (*queue)->first = aux;            (*queue)->size++;            return ;        }        else        {            pQueueNode *iterator = (*queue)->first; //  迭代器            //  插入合适的位置，维护从小到大顺序            while (iterator->next != NULL)            {                if (priority <= iterator->next->priority)                {                    aux->next = iterator->next;                    iterator->next = aux;                    (*queue)->size++;                    return ;                }                iterator = iterator->next;            }            //  当大于队列内所有值，则插入队尾            if (iterator->next == NULL)            {                aux->next = NULL;                iterator->next = aux;                (*queue)->size++;                return ;            }        }    }}//  从队列头逐个取出（越接近头部出现的次数越少）TYPE getPQueue(pQueue **queue){    TYPE returnValue;    if ((*queue)->size > 0)    {        returnValue = (*queue)->first->val;        (*queue)->first = (*queue)->first->next;        (*queue)->size--;    }    else    {        printf("\nQueue is empty.\n");    }    return returnValue;}

huffman

huffman.hpp

#ifndef huffman_hpp#define huffman_hpp#include <stdio.h>typedef struct _htNode  //  树结点{    char symbol;    struct _htNode *left, *right;}htNode;typedef struct _htTree  //  树{    htNode *root;}htTree;typedef struct _hlNode  //  表结点{    char symbol;    char *code;    struct _hlNode *next;}hlNode;typedef struct _hlTable //  表{    hlNode *first;    hlNode *last;}hlTable;htTree *buildTree(char *inputString);               //  构建赫夫曼树hlTable *buildTable(htTree *huffmanTree);           //  构建变长前缀码表void encode(hlTable *table, char *stringToEncode);  //  压缩void decode(htTree *tree, char *stringToDecode);    //  解压#endif /* huffman_hpp */

huffman.cpp

#include "huffman.hpp"#include "queue.hpp"#include <string>#include <stdlib.h>//  创建赫夫曼树htTree *buildTree(char *inputString){    int *probability = (int *)malloc(sizeof(int) * 256);    //  存放ASCII自定义对应的字符    //  初始化    for (int i = 0; i < 256; i++)    {        probability[i] = 0;    }    //  统计待编码的字符串各个字符出现的次数    for (int j = 0; inputString[j] != '\0'; j++)    {        probability[(unsigned char)inputString[j]]++;   //  此处强制转换可有可无    }    //  pQueue队列的头指针    pQueue *huffmanQueue;    initPQueue(&huffmanQueue);    //  填充队列    for (int k = 0; k < 256; k++)    {        if (probability[k] != 0)        {            htNode *aux = (htNode *)malloc(sizeof(htNode));            aux->left = NULL;            aux->right = NULL;            aux->symbol = (char)k;            addPQueue(&huffmanQueue, aux, probability[k]);        }    }    free(probability);  //插入完毕，释放无用内存    //  生成赫夫曼树    while (huffmanQueue->size != 1)    {        int priority = huffmanQueue->first->priority;        priority += huffmanQueue->first->next->priority;        htNode *left = getPQueue(&huffmanQueue);        htNode *right = getPQueue(&huffmanQueue);        htNode *newNode = (htNode *)malloc(sizeof(htNode));        newNode->left = left;        newNode->right = right;        addPQueue(&huffmanQueue, newNode, priority);    }    htTree *tree = (htTree *)malloc(sizeof(htTree));    tree->root = getPQueue(&huffmanQueue);  //  赫夫曼树根结点    return tree;                            //  返回赫夫曼树}//  生成前缀码void traverseTree(htNode *treeNode, hlTable ** table, int k, char code[256]){    if (treeNode->left == NULL && treeNode->right == NULL)  //  存储前缀码    {        code[k] = '\0';        hlNode *aux = (hlNode *)malloc(sizeof(hlNode));        aux->code = (char *)malloc(sizeof(char) * (strlen(code) + 1));        strcpy(aux->code, code);        aux->symbol = treeNode->symbol;        aux->next = NULL;        if ((*table)->first == NULL)        {            (*table)->first = aux;            (*table)->last = aux;        }        else        {            (*table)->last->next = aux;            (*table)->last = aux;        }    }    if (treeNode->left != NULL)     //  如果左孩子不为空，则前缀码填'0'    {        code[k] = '0';        traverseTree(treeNode->left, table, k + 1, code);    }    if (treeNode->right != NULL)    //  如果右孩子不为空，则前缀码填'1'    {        code[k] = '1';        traverseTree(treeNode->right, table, k + 1, code);    }    return ;}//  构建变长前缀码表hlTable *buildTable(htTree *huffmanTree){    hlTable *table = (hlTable *)malloc(sizeof(hlTable));    table->first = NULL;    table->last = NULL;    char code[256];    int k = 0;    traverseTree(huffmanTree->root, &table, k, code);    return table;   //  返回变长前缀码表}//  压缩void encode(hlTable *table, char *stringToEncode){    hlNode *traversal;    printf("Encoding......\nInput string:\n%s\nEncoded string:\n", stringToEncode);    for (int i = 0; stringToEncode[i] != '\0'; i++)    {        traversal = table->first;        while (traversal->symbol != stringToEncode[i])        {            traversal = traversal->next;        }        printf("%s", traversal->code);    }    printf("\n");    return ;}//  解压void decode(htTree *tree, char *stringToDecode){    htNode *traversal = tree->root;    printf("\nDecoding......\nInput string:\n%s\nDecoded string:\n", stringToDecode);    for (int i = 0; stringToDecode[i] != '\0'; i++)    {        if (traversal->left == NULL && traversal->right == NULL)        {            printf("%c", traversal->symbol);            traversal = tree->root;        }        if (stringToDecode[i] == '0')       //  等于'0'向左孩子查找        {            traversal = traversal->left;        }        else /* if (stringToDecode[i] == '1')等于'1'向右孩子查找 */        {            traversal = traversal->right;        }    }    if (traversal->left == NULL && traversal->right == NULL)    {        printf("%c", traversal->symbol);    }    putchar('\n');    return ;}

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