// Minimum spanning tree algorithm
public Graph Kruskal()
{
// Initialization
Graph MST = new Graph(false);
foreach (string vertName in AdjList.Keys)
{
MST.AddVertex(vertName);
}
// disjoint sets of vertices for Kruskal's algorithm
VertexDisjointSets Sets = new VertexDisjointSets();
foreach (Vertex vertex in AdjList.Values)
{
VertexDisjointSets.Node v = new VertexDisjointSets.Node(vertex);
Sets.MakeSet(v);
}
// making set of the edges and sort them
List <Edge> edges = new List <Edge>();
foreach (Vertex fr in AdjList.Values)
{
VertexDisjointSets.Node from = Sets[fr];
foreach (KeyValuePair <Vertex, uint> t in fr.Adj)
{
VertexDisjointSets.Node to = Sets[t.Key];
Edge e = new Edge(from, to, t.Value);
edges.Add(e);
}
}
edges.Sort();
// main part of alg
foreach (Edge edge in edges)
{
if (Sets.FindSet(edge.from) != Sets.FindSet(edge.to))
{
MST.AddEdge(edge.from.vertex.Name, edge.to.vertex.Name, edge.weight);
Sets.Union(edge.from, edge.to);
}
}
return(MST);
}
public Edge(VertexDisjointSets.Node f, VertexDisjointSets.Node t, uint w)
{
from = f;
to = t;
weight = w;
}
