public void TestMST()
{
MST mst = new MST();
mst.AddEdge(1, 2, 1);
mst.AddEdge(1, 3, 3);
mst.AddEdge(1, 4, 4);
mst.AddEdge(2, 3, 2);
mst.AddEdge(3, 4, 5);
mst.Execute();
Assert.AreEqual(7, mst.Cost);
}
// Prim's MST
public override void GenerateMST()
{
Init();
for (int i = 0; i < graph.Size; i++)
{
int v = FindMinimumDistance();
var newDistance = distance[v];
if (newDistance < INFINITY)
{
componentOfMST[v] = true;
var v1 = graph.GetVertexByID((uint)v);
var v2 = neighbor[v];
var edge = new Edge <V, int>(v1, v2);
MST.AddEdge(edge);
foreach (var w in graph.GetNeighbours(v1))
{
var e2 = graph.GetEdge(v1, w);
if (!componentOfMST[w.ID] && e2.Value < distance[w.ID])
{
distance[w.ID] = e2.Value;
neighbor[w.ID] = v1;
}
}
}
else
{
break;
}
}
}
// Kruskal's MST
/*
* 1. Sort edges by decresing weight
* 2. Pick the first edge with lowest weight
* 3. Detect cycle
* 4. Add to graph if not cycle
*/
public override void GenerateMST()
{
var edgeEnum = graph.Edges.OrderBy(e => e.Value);
foreach (var nextEdge in edgeEnum)
{
var isCycle = unionFind.IsCycle((int)nextEdge.Start.ID, (int)nextEdge.End.ID);
if (!isCycle)
{
MST.AddEdge(nextEdge);
}
}
}
static void Main(string[] args)
{
var mst = new MST();
string line;
using (StreamReader srStreamRdr = new StreamReader(@"edges.txt"))
{
while ((line = srStreamRdr.ReadLine()) != null)
{
string[] values = line.Split(new Char[] { ' ' });
mst.AddEdge(int.Parse(values[0]), int.Parse(values[1]), int.Parse(values[2]));
}
}
mst.Execute();
Console.WriteLine(mst.Cost);
Console.ReadKey();
}
// Prim's MST
public override void GenerateMST()
{
Init();
while (!queue.Empty)
{
var e = queue.Dequeue();
var v = e.Start;
var w = e.End;
if (componentOfMST[v.ID] && componentOfMST[w.ID])
{
continue;
}
MST.AddEdge(e);
Visit(v);
Visit(w);
}
}