FindMinimumSpanningTree(WeightedGraph <T, TW> graph)
{
var edges = new List <MSTEdge <T, TW> >();
//gather all unique edges
dfs(graph.ReferenceVertex, new System.Collections.Generic.HashSet <T>(),
new Dictionary <T, System.Collections.Generic.HashSet <T> >(),
edges);
//quick sort preparation
var sortArray = new MSTEdge <T, TW> [edges.Count];
for (int i = 0; i < edges.Count; i++)
{
sortArray[i] = edges[i];
}
//quick sort edges
var sortedEdges = MergeSort <MSTEdge <T, TW> > .Sort(sortArray);
var result = new List <MSTEdge <T, TW> >();
var disJointSet = new DisJointSet <T>();
//create set
foreach (var vertex in graph.Vertices)
{
disJointSet.MakeSet(vertex.Key);
}
//pick each edge one by one
//if both source & target belongs to same set
//then don't add the edge to result
//otherwise add it to result and union sets
for (int i = 0; i < edges.Count; i++)
{
var currentEdge = sortedEdges[i];
var setA = disJointSet.FindSet(currentEdge.Source);
var setB = disJointSet.FindSet(currentEdge.Destination);
//can't pick edge with both ends already in MST
if (setA.Equals(setB))
{
continue;
}
result.Add(currentEdge);
//union picked edge vertice sets
disJointSet.Union(setA, setB);
}
return(result);
}
public int CompareTo(MSTEdge <T, W> other)
{
return(Weight.CompareTo(other.Weight));
}
