求输入一串字符串，根据给定的字符串中字符出现的频率建立相应的哈夫曼树，构造哈夫曼编码表，在此基础上可以对压缩文件进行压缩(即编码)，同时可以对压缩后的二进制编码文件进行解压(即译码)C语言代码

以下是一个简单的C语言实现哈夫曼编码的示例代码，同时包含压缩和解压功能。请注意，这只是一个示例代码，实际情况下需要更加完善和优化：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define MAX_TREE_HT 100

struct MinHeapNode {
    char data;
    unsigned freq;
    struct MinHeapNode *left, *right;
};

struct MinHeap {
    unsigned size;
    unsigned capacity;
    struct MinHeapNode** array;
};

struct MinHeapNode* newNode(char data, unsigned freq) {
    struct MinHeapNode* temp = (struct MinHeapNode*)malloc(sizeof(struct MinHeapNode));
    temp->left = temp->right = NULL;
    temp->data = data;
    temp->freq = freq;
    return temp;
}

struct MinHeap* createMinHeap(unsigned capacity) {
    struct MinHeap* minHeap = (struct MinHeap*)malloc(sizeof(struct MinHeap));
    minHeap->size = 0;
    minHeap->capacity = capacity;
    minHeap->array = (struct MinHeapNode**)malloc(minHeap->capacity * sizeof(struct MinHeapNode*));
    return minHeap;
}

void swapMinHeapNode(struct MinHeapNode** a, struct MinHeapNode** b) {
    struct MinHeapNode* t = *a;
    *a = *b;
    *b = t;
}

void minHeapify(struct MinHeap* minHeap, int idx) {
    int smallest = idx;
    int left = 2 * idx + 1;
    int right = 2 * idx + 2;
    if (left < minHeap->size && minHeap->array[left]->freq < minHeap->array[smallest]->freq) {
        smallest = left;
    }
    if (right < minHeap->size && minHeap->array[right]->freq < minHeap->array[smallest]->freq) {
        smallest = right;
    }
    if (smallest != idx) {
        swapMinHeapNode(&minHeap->array[smallest], &minHeap->array[idx]);
        minHeapify(minHeap, smallest);
    }
}

int isSizeOne(struct MinHeap* minHeap) {
    return (minHeap->size == 1);
}

struct MinHeapNode* extractMin(struct MinHeap* minHeap) {
    struct MinHeapNode* temp = minHeap->array[0];
    minHeap->array[0] = minHeap->array[minHeap->size - 1];
    --minHeap->size;
    minHeapify(minHeap, 0);
    return temp;
}

void insertMinHeap(struct MinHeap* minHeap, struct MinHeapNode* minHeapNode) {
    ++minHeap->size;
    int i = minHeap->size - 1;
    while (i && minHeapNode->freq < minHeap->array[(i - 1) / 2]->freq) {
        minHeap->array[i] = minHeap->array[(i - 1) / 2];
        i = (i - 1) / 2;
    }
    minHeap->array[i] = minHeapNode;
}

void buildMinHeap(struct MinHeap* minHeap) {
    int n = minHeap->size - 1;
    int i;
    for (i = (n - 1) / 2; i >= 0; --i) {
        minHeapify(minHeap, i);
    }
}

void printArr(int arr[], int n) {
    int i;
    for (i = 0; i < n; ++i) {
        printf("%d", arr[i]);
    }
    printf("\n");
}

int isLeaf(struct MinHeapNode* root) {
    return !(root->left) && !(root->right);
}

struct MinHeap* createAndBuildMinHeap(char data[], int freq[], int size) {
    struct MinHeap* minHeap = createMinHeap(size);
    for (int i = 0; i < size; ++i) {
        minHeap->array[i] = newNode(data[i], freq[i]);
    }
    minHeap->size = size;
    buildMinHeap(minHeap);
    return minHeap;
}

struct MinHeapNode* buildHuffmanTree(char data[], int freq[], int size) {
    struct MinHeapNode *left, *right, *top;
    struct MinHeap* minHeap = createAndBuildMinHeap(data, freq, size);
    while (!isSizeOne(minHeap)) {
        left = extractMin(minHeap);
        right = extractMin(minHeap);
        top = newNode('$', left->freq + right->freq);
        top->left = left;
        top->right = right;
        insertMinHeap(minHeap, top);
    }
    return extractMin(minHeap);
}

void printCodes(struct MinHeapNode* root, int arr[], int top) {
    if (root->left) {
        arr[top] = 0;
        printCodes(root->left, arr, top + 1);
    }
    if (root->right) {
        arr[top] = 1;
        printCodes(root->right, arr, top + 1);
    }
    if (isLeaf(root)) {
        printf("%c: ", root->data);
        printArr(arr, top);
    }
}

void HuffmanCodes(char data[], int freq[], int size) {
    struct MinHeapNode* root = buildHuffmanTree(data, freq, size);
    int arr[MAX_TREE_HT], top = 0;
    printCodes(root, arr, top);
}

void encode(char *str, char *output) {
    char data[256];
    int freq[256] = {0};
    int i = 0;
    while (str[i] != '\0') {
        freq[(int)str[i]]++;
        i++;
    }
    int size = 0;
    for (i = 0; i < 256; i++) {
        if (freq[i] != 0) {
            data[size++] = (char)i;
        }
    }
    HuffmanCodes(data, freq, size);

    // create the Huffman code table
    int codeTable[256][MAX_TREE_HT];
    int codeTableSize[256] = {0};
    int arr[MAX_TREE_HT], top = 0;
    printCodes(root, arr, top);
    for (i = 0; i < 256; i++) {
        if (freq[i] != 0) {
            for (int j = 0; j < top; j++) {
                codeTable[i][j] = arr[j];
            }
            codeTableSize[i] = top;
        }
    }

    // encode the string
    i = 0;
    int j = 0;
    while (str[i] != '\0') {
        int c = (int)str[i];
        for (int k = 0; k < codeTableSize[c]; k++) {
            output[j++] = codeTable[c][k] + '0';
        }
        i++;
    }
    output[j] = '\0';
}

void decode(char *input, char *output) {
    int freq[256] = {0};
    int i = 0;
    while (input[i] != '\0') {
        freq[input[i] - '0']++;
        i++;
    }
    char data[256];
    int size = 0;
    for (i = 0; i < 256; i++) {
        if (freq[i] != 0) {
            data[size++] = (char)i;
        }
    }
    struct MinHeapNode* root = buildHuffmanTree(data, freq, size);

    // decode the string
    struct MinHeapNode* curr = root;
    i = 0;
    int j = 0;
    while (input[i] != '\0') {
        if (input[i] == '0') {
            curr = curr->left;
        } else {
            curr = curr->right;
        }
        if (isLeaf(curr)) {
            output[j++] = curr->data;
            curr = root;
        }
        i++;
    }
    output[j] = '\0';
}

int main() {
    char str[] = "hello world";
    char output[1000];
    char decoded[1000];

    // encode the string
    encode(str, output);
    printf("Encoded string: %s\n", output);

    // decode the string
    decode(output, decoded);
    printf("Decoded string: %s\n", decoded);

    return 0;
}