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Thread: Retrieving BFS code's adjacency list

  1. #1
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    Default Retrieving BFS code's adjacency list

    I am trying to create a bfs program but I am getting stuck with the Node class ArrayList retrieval part. I am trying to create 28 nodes, each with their own adjacency list. I want to retrieve the adjacency list from any given node so i can perform operations based on the node mapped to the string in the adjacency list. When I try to retrieve the adjacency list, it comes back empty when there should be, for example in node 1, a list with the string 2, 4, 5. this way i can get the node mapped to the string key "2", etc.The code is:

    class Node{
    String name;
    ArrayList<String> list;
     
     
    public Node(){}
     
    public Node( String name, ArrayList<String> list){
    this.name = name;
    this.list = list;
     
    for( String n : list ){
    System.out.println("DEBUG: test if list got passed in " + n );
    }//it does print the list elements
     
     
    }
    }
     
     
    public static void BFS(){
     
    //Queue<Node> q = new LinkedList<Node> ();
    Vector<Node> q = new Vector<Node> ();
     
     
    Map<String, Node> allNodes = new HashMap<String, Node> (28);
     
     
    ArrayList<String> l = new ArrayList<String>();
    l.add("2");
    l.add("4");
    l.add("5");
    Node One = new Node("1", l);
    allNodes.put("1", One );
     
    // clear l so it can contain new elements to be sent to Node constructor
    l.clear();
     
    l.add("3");
    l.add("6");
    Node Two = new Node("2", l);
    allNodes.put("2", Two);
     
    l.clear()
     
    Node j = allNodes.get("1");
    System.out.println("J = 1---- J's name = " +j.name);
    System.out.println("J's list = " +j.list);
    ....}

    The output i get is:

    DEBUG: test if list got passed in 2
    DEBUG: test if list got passed in 4
    DEBUG: test if list got passed in 5
    J = 1---- J's name = 1
    J's list = []

    the list is empty. I want it to retrieve the nodes adjacency list. How do I fix this?

    Thanks in advance

    I also attached the full code file for people but its not needed for my question i believe.
    Attached Files Attached Files


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