用c++实现哈夫曼树

以下是用C++实现哈夫曼树的代码示例：

#include <iostream>
#include <queue>
#include <vector>
using namespace std;

// 定义哈夫曼树结点
struct HuffmanNode {
    int weight; // 权重
    char ch; // 字符
    HuffmanNode *left, *right; // 左右子树指针
    HuffmanNode(int w, char c) : weight(w), ch(c), left(nullptr), right(nullptr) {}
};

// 定义比较函数，用于优先队列
struct cmp {
    bool operator()(HuffmanNode* a, HuffmanNode* b) {
        return a->weight > b->weight;
    }
};

// 构造哈夫曼树
HuffmanNode* buildHuffmanTree(vector<int>& weights, vector<char>& chars) {
    priority_queue<HuffmanNode*, vector<HuffmanNode*>, cmp> pq;
    for (int i = 0; i < weights.size(); i++) {
        pq.push(new HuffmanNode(weights[i], chars[i]));
    }
    while (pq.size() > 1) {
        HuffmanNode* left = pq.top();
        pq.pop();
        HuffmanNode* right = pq.top();
        pq.pop();
        HuffmanNode* parent = new HuffmanNode(left->weight + right->weight, '\0');
        parent->left = left;
        parent->right = right;
        pq.push(parent);
    }
    return pq.top();
}

// 遍历哈夫曼树，生成哈夫曼编码
void generateHuffmanCode(HuffmanNode* root, string code, vector<string>& codes) {
    if (!root) {
        return;
    }
    if (root->ch != '\0') {
        codes[root->ch] = code;
    }
    generateHuffmanCode(root->left, code + "0", codes);
    generateHuffmanCode(root->right, code + "1", codes);
}

// 主函数
int main() {
    vector<int> weights = {5, 9, 12, 13, 16, 45};
    vector<char> chars = {'a', 'b', 'c', 'd', 'e', 'f'};
    HuffmanNode* root = buildHuffmanTree(weights, chars);
    vector<string> codes(128);
    generateHuffmanCode(root, "", codes);
    for (int i = 0; i < 128; i++) {
        if (!codes[i].empty()) {
            cout << (char)i << ": " << codes[i] << endl;
        }
    }
    return 0;
}