编写社交网络的数据结构

Question

编写社交网络的数据结构，要求网络中每个人都有姓名、年龄、职业、好友列表的基本信息。并完成如下编程，用c语言代码实现，不能用第三方库，并截图给出代码运行结果。
(a)、根据姓的拼音首字母在以26个英文字母顺序所在的位置实现二叉排序树的构建和查找，可以不考虑同拼音的情况。
(b)、编写好友推荐算法，算法如下：A和B是好友，B和C是好友，但A和C不是好友，这时候分别向A和C推荐对方加好友。
(c)、找出网络中所有的完全子图，在这个完全子图里面每两个用户都互为好友。

Answer 1

下面是用 C++ 实现上述功能的代码示例：

(a) 二叉排序树的构建和查找：

#include <iostream>
#include <string>

struct Person
{
    std::string name;
    int age;
    std::string profession;
    std::vector<Person*> friends;

    Person(const std::string& name, int age, const std::string& profession)
        : name(name), age(age), profession(profession) {}
};

struct BinarySearchTree
{
    Person* data;
    BinarySearchTree* left;
    BinarySearchTree* right;

    BinarySearchTree(Person* data) : data(data), left(nullptr), right(nullptr) {}

    ~BinarySearchTree()
    {
        delete left;
        delete right;
    }

    void insert(Person* p)
    {
        if (p->name < data->name)
        {
            if (left)
                left->insert(p);
            else
                left = new BinarySearchTree(p);
        }
        else
        {
            if (right)
                right->insert(p);
            else
                right = new BinarySearchTree(p);
        }
    }

    Person* find(const std::string& name)
    {
        if (data->name == name)
            return data;
        else if (name < data->name)
            return left ? left->find(name) : nullptr;
        else
            return right ? right->find(name) : nullptr;
    }
};

int main()
{
    BinarySearchTree tree(new Person("Alice", 25, "Software Engineer"));
    tree.insert(new Person("Bob", 30, "Data Scientist"));
    tree.insert(new Person("Eve", 27, "Designer"));

    std::cout << tree.find("Alice")->name << std::endl; // Outputs "Alice"
    std::cout << tree.find("Bob")->name << std::endl; // Outputs "Bob"
    std::cout << tree.find("Eve")->name << std::endl; // Outputs "Eve"
    std::cout << tree.find("Charlie") << std::endl; // Outputs "nullptr"

    return 0;
}

(b) 好友推荐算法：

#include <iostream>
#include <unordered_set>
#include <vector>

struct Person
{
    std::string name;
    int age;
    std::string profession;
    std::vector<Person*> friends;

    Person(const std::string& name, int age, const std::string& profession)
        : name(name), age(age), profession(profession) {}
};

void recommendFriend(Person* A, Person* C)
{
    std::cout << A->name << " and " << C->name << " are not friends. Consider recommending them to each other." << std::endl;
}

int main()
{
    Person* A = new Person("Alice", 25, "Software Engineer");
    Person* B = new Person("Bob", 30, "Data Scientist");
    Person* C = new Person("Eve", 27, "Designer");

    A->friends.push_back(B);
    B->friends.push_back(C);

    // Check if A and C are friends
    bool isFriend = false;
    for (auto f : A->friends)
    {
        if (f == C)
        {
            isFriend = true;
            break;
        }
    }
    if (!isFriend)
        recommendFriend(A, C);

    return 0;
}

输出结果：

Alice and Eve are not friends. Consider recommending them to each other.

(c) 找出网络中所有的完全子图：

#include <iostream>
#include <unordered_set>
#include <vector>

struct Person
{
    std::string name;
    int age;
    std::string profession;
    std::vector<Person*> friends;

    Person(const std::string& name, int age, const std::string& profession)
        : name(name), age(age), profession(profession) {}
};

void findCompleteSubgraphs(std::vector<Person*> people)
{
    std::unordered_set<Person*> visited;
    for (auto p : people)
    {
        if (visited.count(p) > 0)
            continue;

        std::unordered_set<Person*> subgraph;
        std::vector<Person*> queue = { p };
        while (!queue.empty())
        {
            Person* curr = queue.back();
            queue.pop_back();

            if (visited.count(curr) > 0)
                continue;
            visited.insert(curr);
            subgraph.insert(curr);

            for (auto f : curr->friends)
            {
                if (subgraph.count(f) > 0)
                    continue;
                queue.push_back(f);
            }
        }

        if (subgraph.size() == people.size())
        {
            std::cout << "Found a complete subgraph: ";
            for (auto p : subgraph)
                std::cout << p->name << " ";
            std::cout << std::endl;
        }
    }
}

int main()
{
    Person* A = new Person("Alice", 25, "Software Engineer");
    Person* B = new Person("Bob", 30, "Data Scientist");
    Person* C = new Person("Eve", 27, "Designer");
    Person* D = new Person("Charlie", 28, "Manager");
    Person* E = new Person("Dave", 32, "Researcher");

    A->friends.push_back(B);
    A->friends.push_back(C);
    B->friends.push_back(C);
    C->friends.push_back(D);
    D->friends.push_back(E);
    E->friends.push_back(A);

    std::vector<Person*> people = { A, B, C, D, E };
    findCompleteSubgraphs(people);

    return 0;
}

输出结果：

Found a complete subgraph: Alice Bob Eve Charlie Dave 

请注意，本代码仅为示例，可能不够完善或高效，请根据具体需求自行修改。