2012_06_18.java (ex. 3)

// Esame del 18 giugno 2012, esercizio 3
// Ricordarsi di specificare sempre, nei commenti al codice, l'utilità di ogni metodo.
// Per le implementazioni standard di un grafo riferirsi a GraphImplementations.java

class Vertex has String nick; double x; double y; Object profile; and get methods
class Edge has double distance;

public Collection<Vertex> introduction(String nick)
    {
    HashSet<Vertex> people = new HashSet<Vertex>();
    for(Vertex v : vertices)
        {
        if(v.getNick().equals(nick))
            DFS(v, people, new HashSet<Vertex>());
        }
    return people;
    }

public void DFS(Vertex v, HashSet<Vertex> people, HashSet<Vertex> visited)
    {
    visited.put(v);
    for(Edge e : incidentEdges(v))
        {
        Vertex w = opposite(e, v);
        if(!visited.contains(w))
            {
            people.put(w);
            DFS(w, people, visited);
            }
        }
    }

public Collection<Vertex> compatible(String nick, double dist)
    {
    HashSet<Vertex> compatible = new HashSet<Vertex>();
    for(Vertex v : vertices)
        {
        if(v.getNick().equals(nick))
            DFS_C(v, nick, dist, compatible, new HashSet<Vertex>());
        }
    return compatible;
    }

public void DFS_C(Vertex v, String nick, double dist, HashSet<Vertex> compatible, HashSet<Vertex> visited)
    {
    visited.put(v);
    for(Edge e : incidentEdges(v))
        {
        Vertex w = opposite(v);
        if(!visited.contains(w))
            {
            if(compatibili(nick, w.getNick()) && distanzaIstantanea(nick, w.getNick()) <= dist)
                compatible.put(w);
            DFS_C(w, nick, dist, compatible, visited);
            }
        }
    }