哈夫曼树编码选择函数代码c++

以下是C++实现的哈夫曼树编码选择函数代码：

void select(HuffmanTree HT, int n, int &s1, int &s2) {
    int i;
    int min1, min2;
    min1 = min2 = MAXVALUE;
    for (i = 1; i <= n; i++) {
        if (HT[i].parent == 0) {
            if (HT[i].weight < min1) {
                min2 = min1;
                s2 = s1;
                min1 = HT[i].weight;
                s1 = i;
            } else if (HT[i].weight < min2) {
                min2 = HT[i].weight;
                s2 = i;
            }
        }
    }
}

该函数的作用是在哈夫曼树中选择权值最小的两个节点。其中，HT是哈夫曼树，n是叶子节点的个数，s1和s2是指向权值最小的两个节点的指针。该函数的实现过程是遍历哈夫曼树中所有未被标记的节点，找到其中权值最小的两个节点，并将它们的下标分别赋值给s1和s2。

相关问题

根据哈夫曼树求哈夫曼编码的C++代码

下面是一个根据哈夫曼树求哈夫曼编码的C代码示例：

#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);
}

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

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);
}

int main() {
    char arr[] = {'a', 'b', 'c', 'd', 'e', 'f'};
    int freq[] = {5, 9, 12, 13, 16, 45};
    int size = sizeof(arr) / sizeof(arr[0]);
    HuffmanCodes(arr, freq, size);
    return 0;
}

这段代码实现了根据给定字符集的频率构建哈夫曼树，并输出每个字符的哈夫曼编码。其中，`buildHuffmanTree()`函数用于构建哈夫曼树，`printCodes()`函数用于打印每个字符的哈夫曼编码，`main()`函数中给出了一个示例，用于演示如何使用该代码实现哈夫曼编码。

哈夫曼树的设计源代码 C++

以下是哈夫曼树的设计源代码，使用了C++语言：

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

// 定义哈夫曼树节点结构体
struct HuffmanNode {
    int weight; // 权值
    HuffmanNode *leftChild; // 左子节点指针
    HuffmanNode *rightChild; // 右子节点指针

    // 构造函数
    HuffmanNode(int w) {
        weight = w;
        leftChild = rightChild = nullptr;
    }
};

// 定义哈夫曼树类
class HuffmanTree {
private:
    HuffmanNode *root; // 根节点指针

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

public:
    // 构造函数
    HuffmanTree(int weights[], int n) {
        // 创建优先队列
        priority_queue<HuffmanNode*, vector<HuffmanNode*>, cmp> pq;

        // 将每个权值转换为节点，并加入优先队列
        for (int i = 0; i < n; i++) {
            pq.push(new HuffmanNode(weights[i]));
        }

        // 不断取出两个最小的节点，合并为一个新节点，直到队列中只剩一个节点，即为根节点
        while (pq.size() > 1) {
            HuffmanNode *left = pq.top();
            pq.pop();
            HuffmanNode *right = pq.top();
            pq.pop();

            HuffmanNode *newNode = new HuffmanNode(left->weight + right->weight);
            newNode->leftChild = left;
            newNode->rightChild = right;
            pq.push(newNode);
        }

        root = pq.top();
    }

    // 析构函数
    ~HuffmanTree() {
        destroy(root);
    }

    // 销毁哈夫曼树
    void destroy(HuffmanNode *node) {
        if (node != nullptr) {
            destroy(node->leftChild);
            destroy(node->rightChild);
            delete node;
        }
    }

    // 获取哈夫曼编码
    void getHuffmanCode(HuffmanNode *node, string code, string codes[]) {
        if (node->leftChild == nullptr && node->rightChild == nullptr) {
            codes[node->weight] = code;
            return;
        }

        getHuffmanCode(node->leftChild, code + "0", codes);
        getHuffmanCode(node->rightChild, code + "1", codes);
    }

    // 输出哈夫曼编码表
    void printHuffmanCode(string codes[], int n) {
        for (int i = 0; i < n; i++) {
            cout << "字符 " << char(i) << " 的哈夫曼编码为：" << codes[i] << endl;
        }
    }
};

int main() {
    const int n = 6;
    int weights[n] = {2, 3, 7, 10, 4, 2};
    string codes[n];

    HuffmanTree tree(weights, n);
    tree.getHuffmanCode(tree.root, "", codes);
    tree.printHuffmanCode(codes, n);

    return 0;
}

这个代码实现了哈夫曼树的创建、销毁、获取哈夫曼编码以及输出哈夫曼编码表的功能。