Dijkstra算法無限循環

Question

我學習最短路徑算法，和我想要實現的Dijkstra算法，需要從這樣的文件，輸入：

7 
    A 
    B 
    C 
    D 
    E 
    F 
    G 
    A B 21 
    A C 14 
    B E 5 
    B D 7 
    D F 3 
    E C 44 
    E G 53 
    E D 123 
    G F 51 

問題是，當我添加額外的優勢像DB 12有些頂點,:

Dijkstra算法：

public Set<Vertex> dijkstraAlgo(Graph G, int s) { 
    initializeSingleSource(G, s); 
    Set<Vertex> set = new HashSet<Vertex>(); // intitially empty set of 
               // vertexes 

    Queue<Vertex> Q = new PriorityQueue<Vertex>(10, new VertexComparator()); // min 
                       // priority 
                       // queue 

    for (Vertex v : G.vertices) { // add source to priority queue 
     Q.add(G.vertices[s]); 
    } 

    while (Q.size() != 0) { 
     Vertex u = Q.poll(); // extract vertex which have min distance in 
           // priority queue 
     set.add(u); // add that vertex to set 
     for (String vertexId : u.neighbours.keySet()) { // see neighbours of 
      // vertex extracted 
      int vertexNum = indexForName(G, vertexId); 

      Vertex v = G.vertices[vertexNum]; 
      int w = weightFunc(G, u, v); 

      relax(u, v, w); 
      Q.add(v); 
     } 
    } 

    return set; 

} 

讀取文件：

public class Graph { 
Vertex[] vertices; 


public Graph(String file) throws FileNotFoundException{ 
    Scanner sc = new Scanner(new File(file)); 
    vertices=new Vertex[sc.nextInt()]; 

    for (int v = 0; v < vertices.length; v++){ 
    vertices[v] = new Vertex(sc.next()); 
    } 

    while (sc.hasNext()) { 
    int v1= indexForName(sc.next());  //read source vertex 
    String destination=sc.next();  //read destination vertex 

    int w=sc.nextInt();     //read weight of the edge 


    vertices[v1].neighbours.put(destination, w); //put the edge adjacent to source vertex 
    } 
    sc.close(); 

}

MAIN：

public static void main(String[] args) throws FileNotFoundException { 
    String fileName = "Dijikstra.txt"; 
    Dijkstra dijkstra = new Dijkstra(fileName); 

    Set<Vertex> vertexInfo = dijkstra.dijkstraAlgo(dijkstra.graph, 0); 
    System.out 
      .println("Printing min distance of all vertexes from source vertex A "); 
    for (Vertex v : vertexInfo) { 
     System.out.println("Id: " + v.id + " distance: " + v.d + " Comming From " + v.p); 
    } 
} 

VERTEX：

class Vertex{ 
    String id;  
    int d;  //to store min distance from source 
    Vertex p;  //to store last vertex from which min distance is reached 
Map<String,Integer> neighbours; //to store edges of adjacent to the vertex    

    public Vertex(String id){ 
    this.id=id; 
    neighbours=new HashMap<String,Integer>(); 
    } 
} 

Answer 1

for (Vertex v : G.vertices) { // add source to priority queue 
     Q.add(G.vertices[s]); 
    } 

你爲什麼要添加的每個頂點到優先級隊列，而不是剛剛起步的？你的頂點類是什麼樣的？