加权图的邻接列表表示

Question

所以大家，最近我一直在练习很多数据结构，图形等等。我遇到了给定代码的问题。我正在实现一个用邻接列表表示的图。我偶然遇到的问题是当我尝试使用用户输入实现解决方案时。我试图在很多方面做到这一点，但我仍然偶然发现程序中的一些问题。因为我使用的是一个采用整数列表的向量，每当我尝试使用while循环（例如）填充向量时，我不知道为什么，但我无法正确地填充它。由于我的错误从那里开始，我不知道如何继续该计划。如果你们可以给我一些关于如何实现我的代码来处理用户输入的提示，或者甚至给我一个与我合作的类似代码，我将非常感激！

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

一个简单的方法是先询问边数，然后以from to weight格式读取许多以空格分隔的数字三元组。这可以很简单：

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));
}