范式huffman解码 c语言

要解码Huffman编码，需要构建Huffman树，然后根据树的结构进行解码。下面是C语言实现的范例代码：

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

// 定义Huffman树的结点
typedef struct Node {
    unsigned char data; // 字符
    int frequency;      // 字符频率
    struct Node* left;  // 左子树
    struct Node* right; // 右子树
} Node;

// 创建Huffman树的结点
Node* createNode(unsigned char data, int frequency) {
    Node* newNode = (Node*)malloc(sizeof(Node));
    newNode->data = data;
    newNode->frequency = frequency;
    newNode->left = newNode->right = NULL;
    return newNode;
}

// 构建Huffman树
Node* buildHuffmanTree(unsigned char* data, int* frequency, int size) {
    int i, j;

    // 初始化结点数组
    Node** nodes = (Node**)malloc(size * sizeof(Node*));
    for (i = 0; i < size; i++) {
        nodes[i] = createNode(data[i], frequency[i]);
    }

    // 构建树
    while (size > 1) {
        // 找出最小和次小的结点
        int min1 = 0, min2 = 1;
        if (frequency[min1] > frequency[min2]) {
            int temp = min1;
            min1 = min2;
            min2 = temp;
        }

        for (i = 2; i < size; i++) {
            if (frequency[i] < frequency[min1]) {
                min2 = min1;
                min1 = i;
            }
            else if (frequency[i] < frequency[min2]) {
                min2 = i;
            }
        }

        // 创建新的父结点
        Node* parent = createNode('\0', frequency[min1] + frequency[min2]);
        parent->left = nodes[min1];
        parent->right = nodes[min2];

        // 将父结点插入数组
        nodes[min1] = parent;

        // 删除次小的结点
        for (j = min2; j < size - 1; j++) {
            nodes[j] = nodes[j + 1];
            frequency[j] = frequency[j + 1];
        }

        size--;
    }

    // 返回根结点
    return nodes[0];
}

// Huffman解码
void decodeHuffman(Node* root, unsigned char* encodedData, int size) {
    Node* current = root;

    for (int i = 0; i < size; i++) {
        if (encodedData[i] == '0') {
            current = current->left;
        } else {
            current = current->right;
        }

        // 到达叶子结点，输出字符
        if (current->left == NULL && current->right == NULL) {
            printf("%c", current->data);
            current = root;
        }
    }
}

int main() {
    unsigned char data[] = {'A', 'B', 'C', 'D', 'E'};
    int frequency[] = {5, 3, 6, 2, 4};
    int size = sizeof(data) / sizeof(data[0]);

    Node* root = buildHuffmanTree(data, frequency, size);

    unsigned char encodedData[] = "100010101011";
    int encodedSize = sizeof(encodedData) / sizeof(encodedData[0]) - 1;

    decodeHuffman(root, encodedData, encodedSize);

    return 0;
}

范例代码中，首先定义了Huffman树的结点和相应的操作函数。然后，通过构建Huffman树实现了解码函数decodeHuffman。在主函数中，定义了字符数据data和频率frequency，根据这些数据创建Huffman树的根结点root。接下来，定义了编码数据encodedData，并调用decodeHuffman函数对编码数据进行解码。输出结果为解码后的字符。