void Prim2opt::preorderTreeWalk(Grafo<unsigned int> &g, unsigned int v, unsigned int visited[], list<unsigned int> &S) {
    visited[v] = 1;
    S.push_back(v);
    list<unsigned int> adj;
    g.getAdjacents(v, adj);
    list<unsigned int>::iterator it = adj.begin();

    while(it != adj.end()) {
        if(!visited[*it]){
            preorderTreeWalk(g, *it, visited, S);
        }
        it++;
    }
}
Grafo<unsigned int> Prim2opt::getPrim(Grafo<Ciudad> &g, unsigned int vertice) {
	unsigned int N = g.getSize();
	int root[N];
	unsigned int distance[N];
	unsigned int visited[N];

	for (unsigned int i = 0; i < N; i++) {
		distance[i] = INFINITE;
		root[i] = -1;
		visited[i] = 0;
	}

	priority_queue <ui_ui, vector<ui_ui>, greater<ui_ui> > pq;
	distance[vertice] = 0;
	pq.push(ui_ui(0, vertice));
	while (!pq.empty()){
		unsigned int aux = pq.top().second;
		pq.pop();
		if (visited[aux] == 1)
			continue;
		visited[aux] = 1;
		list<unsigned int> adj;
		g.getAdjacents(aux, adj);
		list<unsigned int>::iterator it = adj.begin();
		while (it != adj.end()){
			unsigned int dist = g.getData(aux, *it).getCost();
			if (dist < distance[*it] && !visited[*it]){
				distance[*it] = dist;
				root[*it] = aux;
				pq.push(ui_ui(dist,*it));
			}

			it++;
		}
	}

	Grafo<unsigned int> mst = getMinimumSpanningTree(root, distance, N, vertice);
	return mst;

}