Question

所以，伙计们，最近我在数据结构，图形等方面进行了大量练习。给定的代码遇到了问题。我正在实现一个用邻接表表示的图形。我偶然遇到的问题是当我尝试使用用户输入来实现该解决方案时。我尝试了许多方法来做，但是我仍然偶然发现程序中的一些问题。因为我使用的矢量需要一个整数列表，所以每当我尝试用while循环（例如）填充矢量时，我都不知道为什么，但是我不能完全正确地填充它。而且由于我的错误甚至从那里开始，所以我不知道如何继续执行该程序。如果你们能给我一些有关如何实现我的代码以与用户输入配合使用的提示，或者甚至给我一个与我一起使用的类似代码，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

一种简单的方法是要求前面的边数，然后读取from to weight格式的许多空格分隔的三元组。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));
}

加权图的邻接表表示

1 个答案: