Dijkstra算法-优先级队列问题

Question

    public void dijkstra() throws IOException {
    buildGraph_u();
    PriorityQueue<Node> pq = new PriorityQueue<>(200, new Node());

    for (int y = 0; y < input.size(); y++) {
        Node v = input.get(array.get(y));
        v.dist = 99999;
        v.known = false;
        v.prnode = null;
        pq.add(v);
    }

    source.dist = 0;
    source.known = true;
    source.prnode = null;
    int c=1;
    while(c != input.size()) {
        Node v = pq.remove();
        //System.out.println(v.name);
                    //^ Prints a node that isn't the source
        v.known = true;
        c++;
        List<Edge> listOfEdges = getAdjacent(v);
        for (int x = 0; x < listOfEdges.size(); x++) {
            Edge edge = listOfEdges.get(x);
            Node w = edge.to;
            if (!w.known) {
                int cvw = edge.weight;
                if (v.dist + cvw < w.dist) {
                    w.dist = v.dist + cvw;
                    w.prnode = v;
                }
            }
        }
    }
}

public int compare (Node d1, Node d2) {
       int dist1 = d1.dist;
       int dist2 = d2.dist;
       if (dist1 > dist2) 
         return 1;
       else if (dist1 < dist2) 
         return -1;
       else 
         return 0;
     }

有人能帮我找到我的PQ的问题吗？

Answer 1

优先级队列使用的假设是，插入元素后顺序不会改变。

因此，不必将所有元素插入优先级队列，您可以：

>

从一个节点开始。