public Kruskal(WeightedGraph G)
{
var V = G.V();
var uf = new QuickUnion(V);
var pq = new MinPQ <Edge>();
mst = new List <Edge>();
foreach (Edge e in G.edges())
{
pq.Enqueue(e);
}
while (!pq.IsEmpty && mst.Count < V - 1)
{
var e = pq.DelMin();
var v = e.either();
var w = e.other(v);
if (!uf.IsConnected(v, w))
{
uf.Union(v, w);
mst.Add(e);
}
}
}
private void visit(WeightedGraph G, int v)
{
marked[v] = true;
foreach (var e in G.adj(v))
{
var w = e.other(v);
if (!marked[w])
{
pq.Enqueue(e);
}
}
}
public void TestMinPQ()
{
MinPQ <int> pq = new MinPQ <int>();
for (var i = 0; i < 100; ++i)
{
pq.Enqueue(99 - i);
}
Assert.Equal(100, pq.Count);
Assert.False(pq.IsEmpty);
for (var i = 0; i < 100; ++i)
{
Assert.Equal(i, pq.DelMin());
Assert.Equal(99 - i, pq.Count);
}
Assert.True(pq.IsEmpty);
}
public LazyPrim(WeightedGraph G)
{
var V = G.V();
marked = new bool[V];
pq = new MinPQ <Edge>();
var s = 0;
foreach (var e in G.adj(s))
{
pq.Enqueue(e);
}
mst = new List <Edge>();
while (!pq.IsEmpty && mst.Count < V - 1)
{
var e = pq.DelMin();
var v = e.either();
var w = e.other(v);
if (marked[v] && marked[w])
{
continue;
}
mst.Add(e);
if (!marked[v])
{
visit(G, v);
}
if (!marked[w])
{
visit(G, w);
}
}
}