/// <summary>
/// Main logic of Kruskal's MST algorithm using disjoint sets
/// </summary>
/// <param name="gr">Researched graph</param>
/// <returns></returns>
private static List <WeightedEdge> Kruskal_MST_sec(Graph gr)
{
List <WeightedEdge> tree = new List <WeightedEdge>();
List <DJS> sets = new List <DJS>();
DJSUtils ut = new DJSUtils(sets);
for (int i = 0; i < gr.Size; i++)
{
ut.MAKE_SET(i); //O(V)
}
WeightedEdge[] grE = gr.GetSortedEdges(); //O(E logE)
foreach (WeightedEdge edge in grE) //O(E)
{
//consider edge (u,v)
int u = edge.Src;
int v = edge.Dest;
DJS uSet = ut.FIND_SET(u).Set;
DJS vSet = ut.FIND_SET(v).Set;
if (uSet != vSet)
{
tree.Add(edge);
ut.UNION(uSet, vSet, (s1, s2) => {
if (s1.Size > s2.Size)
{
return(1);
}
if (s1.Size < s2.Size)
{
return(-1);
}
return(0);
});
}
}
return(tree);
}
public Node(DJS set, int vtx, Node nextNode)
{
Set = set;
Vtx = vtx;
NextNode = nextNode;
}
public Node(DJS set, int vtx)
{
Set = set;
Vtx = vtx;
NextNode = null;
}
