void countEducation() { map<string, map<string, int>> departmentCount; Node* p = head->next; while (p != nullptr) { string department = p->data.getDepartment(); string education = p->data.getEducation(); departmentCount[department][education]++; p = p->next; } for (auto it1 : departmentCount) { cout << it1.first << endl; for (auto it2 : it1.second) { cout << " " << it2.first << "：" << it2.second << endl; } } }这段代码应该如何优化改进？

这段代码可以考虑使用引用类型来避免不必要的复制操作，同时可以使用auto关键字来简化迭代器的声明。

代码示例：

void countEducation() {
    map<string, map<string, int>> departmentCount;
    Node* p = head->next;
    while (p != nullptr) {
        string& department = p->data.getDepartment();
        string& education = p->data.getEducation();
        departmentCount[department][education]++;
        p = p->next;
    }
    for (auto& [department, educationCount] : departmentCount) {
        cout << department << endl;
        for (auto& [education, count] : educationCount) {
            cout << " " << education << "：" << count << endl;
        }
    }
}

另外，可以在Node类中添加访问器函数，使得数据的访问更加安全和直观。例如：

class Node {
public:
    Teacher& getData() { return data; }
    Node* getNext() { return next; }
    void setNext(Node* node) { next = node; }

private:
    Teacher data;
    Node* next;
};

这样，在遍历链表时，可以使用p->getData().getDepartment()和p->getData().getEducation()来访问数据。