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Priority Queue ArrayList HashMap

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Priority Queue ArrayList HashMap

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I have a HashMap whose key is distance and value is ArrayList which contains a list of vertices which are at a particular distance (i.e. key)

I want to make Priority Queue of HashMap(priority based on keys) to get all the vertices which are at a particular distance at a time.

is it possible to make such priority Queue (unbounded one) ? Could anyone help please ?

You can use class to encapsulate the distance and vertices. Implements the Comparable interface or pass the Comparator object when you'll new the PriorityQueue. you can do this following ...

class Node implements Comparable<Node> {
  int distance;
  List<Vertex> list;

  public Node(int distance, List<Vertex> list) {
    this.distance = distance;
    this.list = list;
  }

  @Override
  public int compareTo(Node o) {

      // your compare logic goes here
      return Integer.compare(this.distance, o.distance);
  }
}

=====

public static void main(String[] args) {

    PriorityQueue<Node> q = new PriorityQueue<>();

}

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