赋权图的邻接表表示法

Question

所以，伙计们，最近我一直在练习数据结构，图形等，我遇到了一个问题，与给定的代码。我正在实现一个图，它由一个邻接list.The问题表示，当我试图使用用户输入来实现解决方案时，我偶然遇到了这个问题。我尝试过很多方法，但我还是在程序中遇到了一些问题。因为我使用了一个接受整数列表的向量，所以每当我尝试用while循环填充向量时(例如)，我不知道为什么，但我不能完全正确地填充它。因为我的错误是从那里开始的，所以我不知道如何继续这个程序。如果你们能给我一些关于如何实现我的代码来处理用户输入的提示，或者甚至给我一个类似的代码，我将不胜感激！

这是我的代码：

const int N = 4;

//purpose of the class is to tell what the weight of the given edge is
class Edge{
   private:
       double weight;
       int vertex_id;

   public:
    //constructor that initializes the weight and vertex id

    Edge(double w, int id)
    {
        weight = w;
       vertex_id = id;
    }

    double getWeight() const
        {
            return weight;
        }

    int getId() const
    {
        return vertex_id;
    }
};

int main()
{
    std::vector<std::list<Edge>> adjList(N); //creating our vector that will store a list of integers

    adjList[0].push_back(Edge(4,1)); //pushing back the first neighbours of our Zero list
    adjList[0].push_back(Edge(2,2)); //pushing back the second neighbours of our Zero list and so on...

    adjList[1].push_back(Edge(4,0));
    adjList[1].push_back(Edge(5,2));

    adjList[2].push_back(Edge(2,0));
    adjList[2].push_back(Edge(5,1));
    adjList[2].push_back(Edge(1,3));

    adjList[3].push_back(Edge(1,2));

    std::vector<std::list<Edge>>::iterator i; //declaring our vector iterator

    int c = 0; //we create a counter(and ofcourse assign zero to it)


    //create the for loop, where the iterator starts at the begining of the vector
    //and ends when the vector (adjList) ends


    //*KEEP IN MIND THAT THE FIRST FOR LOOP ONLY ITERATES THROUGH THE NODES OF THE VECTOR
    for (std::vector<std::list<Edge>>::iterator i = adjList.begin(); i != adjList.end(); i++)
    {

        cout << "Vertices connected to our node: " << c << endl;
        std::list<Edge> li = *i; //this pointer serves the purpose to get the list for each different node

        //NOW THE SECOND FOR LOOP ITERATES THROUGH THE LISTS, THAT EACH NODE CONTAINS
        for (std::list<Edge>::iterator iter = li.begin(); iter != li.end(); iter++)
        {
            cout << " (V = " << (*iter).getId() << " weight= " << (*iter).getWeight() <<")";
        }

        cout << endl; // we end the line between the different nodes of the vector

        c++; //increment our counter
    }

Answer 1

一种简单的方法是预先询问边缘的数量，然后以from to weight格式读取许多以空格分隔的数字的三元组。这可以像下面这样简单：

int num_edges;
cin >> num_edges;
for (int i = 0; i < num_edges; i++) {
    int from, to, weight;
    cin >> from >> to >> weight;
    adjList[from].push_back(Edge(to, weight));
    // Uncomment this if you want an undirected graph
    // adjList[to].push_back(Edge(from, weight));
}