该代码报了如下错误： 1>D:\my vs2019 program store\AlgorithmsAndDataStructures\AlgorithmsAndDataStructures\bitree.h(196,3): error C4996: 'strcpy': This function or variable may be unsafe. Consider using strcpy_s instead. To disable deprecation, use _CRT_SECURE_NO_WARNINGS. See online help for details.

这个错误是因为 `strcpy` 被认为是不安全的函数，可以使用 `strcpy_s` 替代。`strcpy_s` 是 C11 标准新增的函数，它会在执行时检测缓冲区边界，从而避免缓冲区溢出的问题。

以下是修改后的代码：

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

typedef struct {
    int weight;  // 权重
    int parent, lchild, rchild;  // 父节点，左子节点，右子节点的下标
} HTNode, * HuffmanTree;

typedef char** HuffmanCode;

void CreateHuffmanTree(HuffmanTree& HT, int n) {
    HT = new HTNode[2 * n - 1];
    for (int i = 0; i < n; i++) {
        cin >> HT[i].weight;
        HT[i].parent = -1;
        HT[i].lchild = -1;
        HT[i].rchild = -1;
    }
    for (int i = n; i < 2 * n - 1; i++) {
        int min1 = INT_MAX, min2 = INT_MAX;
        int min1_idx = -1, min2_idx = -1;
        for (int j = 0; j < i; j++) {
            if (HT[j].parent == -1 && HT[j].weight < min1) {
                min2 = min1;
                min2_idx = min1_idx;
                min1 = HT[j].weight;
                min1_idx = j;
            } else if (HT[j].parent == -1 && HT[j].weight < min2) {
                min2 = HT[j].weight;
                min2_idx = j;
            }
        }
        HT[i].weight = min1 + min2;
        HT[i].lchild = min1_idx;
        HT[i].rchild = min2_idx;
        HT[min1_idx].parent = i;
        HT[min2_idx].parent = i;
    }
}

void CreateHuffmanCode(HuffmanTree HT, HuffmanCode& HC, int n) {
    HC = new char*[n];
    char* code = new char[n];
    code[n - 1] = '\0';
    for (int i = 0; i < n; i++) {
        int current = i;
        int parent = HT[current].parent;
        int idx = n - 1;
        while (parent != -1) {
            if (HT[parent].lchild == current) {
                code[--idx] = '0';
            } else {
                code[--idx] = '1';
            }
            current = parent;
            parent = HT[current].parent;
        }
        HC[i] = new char[n - idx];
        strcpy_s(HC[i], n - idx, &code[idx]);
    }
    delete[] code;
}

int main() {
    int n;
    cout << "Enter the number of characters: ";
    cin >> n;
    HuffmanTree HT;
    CreateHuffmanTree(HT, n);
    HuffmanCode HC;
    CreateHuffmanCode(HT, HC, n);
    cout << "Huffman codes:" << endl;
    for (int i = 0; i < n; i++) {
        cout << "Character '" << (char)('a' + i) << "': " << HC[i] << endl;
    }
    delete[] HT;
    for (int i = 0; i < n; i++) {
        delete[] HC[i];
    }
    delete[] HC;
    return 0;
}

现在程序应该可以正常编译和运行了。