public LazyPrimMST(EdgeWeightedGraph G) {
pq = new PriorityQueue<>(Collections.reverseOrder());
marked = new boolean[G.V()];
mst = new LinkedList<>();
visit(G, 0);
while (!pq.isEmpty()) {
Edge e = pq.poll();
int v = e.either();
int w = e.other(v);
if (marked[v] && marked[w]) continue;
mst.offer(e);
if (!marked[v]) visit(G, v);
if (!marked[w]) visit(G, w);
}
}
private void visit(EdgeWeightedGraph G, int v) {
marked[v] = true;
for (Edge e : G.adj(v)) {
if (!marked[e.other(v)]) pq.offer(e);
}
}