8.1. Abstraction

public class SpanningTree implements Comparable<SpanningTree> {
    private final List<Edge> edges;
    private double total_weight;

    public SpanningTree() {
        edges = new ArrayList<>();
    }

    public SpanningTree(SpanningTree tree) {
        edges = new ArrayList<>(tree.getEdges());
        total_weight = tree.getTotalWeight();
    }
}

public List<Edge> getEdges() { return edges; }
public double getTotalWeight() { return total_weight; }
public int size() { return edges.size(); }

public void addEdge(Edge edge) {
    edges.add(edge);
    total_weight += edge.getWeight();
}

@Override
public int compareTo(SpanningTree tree) {
    double diff = total_weight - tree.total_weight;
    if (diff > 0) return 1;
    else if (diff < 0) return -1;
    else return 0;
}

public interface MST {
    public SpanningTree getMinimumSpanningTree(Graph graph);
}