c语言基于哈夫曼树的数据压缩事例

基于哈夫曼树的数据压缩是一种常见的压缩算法，它通过构建哈夫曼树来实现数据的压缩和解压缩。下面是一个C语言的基于哈夫曼树的数据压缩的示例：

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

// 定义哈夫曼树节点结构体
typedef struct HuffmanNode {
    int data; // 数据
    int weight; // 权重
    struct HuffmanNode *left; // 左子节点
    struct HuffmanNode *right; // 右子节点
} HuffmanNode;

// 创建哈夫曼树
HuffmanNode* createHuffmanTree(int data[], int weight[], int n) {
    HuffmanNode **nodes;
    nodes = (HuffmanNode**)malloc(sizeof(HuffmanNode*) * n);
    for (int i = 0; i < n; i++) {
        nodes[i] = (HuffmanNode*)malloc(sizeof(HuffmanNode));
        nodes[i]->data = data[i];
        nodes[i]->weight = weight[i];
        nodes[i]->left = NULL;
        nodes[i]->right = NULL;
    }

    while (n > 1) {
        int min1 = 0, min2 = 1;
        for (int i = 0; i < n; i++) {
            if (nodes[i]->weight < nodes[min1]->weight) {
                min2 = min1;
                min1 = i;
            } else if (nodes[i]->weight < nodes[min2]->weight) {
                min2 = i;
            }
        }

        HuffmanNode *newNode = (HuffmanNode*)malloc(sizeof(HuffmanNode));
        newNode->data = -1;
        newNode->weight = nodes[min1]->weight + nodes[min2]->weight;
        newNode->left = nodes[min1];
        newNode->right = nodes[min2];

        nodes[min1] = newNode;
        nodes[min2] = nodes[n - 1];
        n--;
    }

    return nodes[0];
}

// 哈夫曼编码
void huffmanEncoding(HuffmanNode *root, int code[], int depth) {
    if (root == NULL) {
        return;
    }

    if (root->data != -1) {
        printf("%d: ", root->data);
        for (int i = 0; i < depth; i++) {
            printf("%d", code[i]);
        }
        printf("\n");
    }

    code[depth] = 0;
    huffmanEncoding(root->left, code, depth + 1);

    code[depth] = 1;
    huffmanEncoding(root->right, code, depth + 1);
}

int main() {
    int data[] = {1, 2, 3, 4, 5};
    int weight[] = {5, 4, 3, 2, 1};
    int n = sizeof(data) / sizeof(data[0]);

    HuffmanNode *root = createHuffmanTree(data, weight, n);

    int code[100];
    huffmanEncoding(root, code, 0);

    return 0;
}

这个示例中，我们首先定义了一个哈夫曼树节点的结构体，然后通过`createHuffmanTree`函数创建哈夫曼树。接下来，我们使用`huffmanEncoding`函数对哈夫曼树进行编码，输出每个节点的编码结果。