public LazyPrimMST(EdgeWeightedGraph G) {
pq = new MinPQ<Edge>(G.E());
mst = new Queue<Edge>();
marked = new boolean[G.V()];
visit(G, 0);
while (!pq.isEmpty()) {
Edge e = pq.delMin();
int v = e.either();
int w = e.other(v);
if (marked[v] && marked[w]) continue;
mst.enqueue(e);
if (!marked[v]) visit(G, v);
else visit(G, w);
}
}
