时间戳

首页 > 解决方案 > 加权图的邻接表表示

c++ - 加权图的邻接表表示

问题描述

所以伙计们，最近我一直在练习数据结构、图形等。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表。我偶然发现的问题是当我尝试使用用户输入来实现解决方案时。我已经尝试以多种方式做到这一点，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带有整数列表的向量，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。而且由于我的错误甚至从那里开始，我不知道如何继续该程序。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，或者甚至给我一个我使用的类似代码，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
    }

标签： c++c++11

解决方案

一种简单的方法是预先询问边的数量，然后以from to weight. 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));
}

推荐阅读