/**********************************************************
*
* Kruskal's minimum spanning tree algorithm
*
**********************************************************/
public Edge[] MST_Kruskal()
{
int ei, i = 0;
Edge e;
int uSet, vSet;
UnionFindSets partition;
int wgt_sum = 0;
// create edge array to store MST
// Initially it has no edges.
mst = new Edge[V-1];
// priority queue for indices of array of edges
Heap h = new Heap(E, edge);
// create partition of singleton sets for the vertices
partition = new UnionFindSets(V);
partition.showSets();
//Comment this code out if you want to see what is inside the heap at each step
//Console.WriteLine("Heap content is:");
//h.display();
while(i < V-1)
{
ei = h.remove();
//I used the commented code to see how are elements removed from the heap each time
//Console.WriteLine("\nRemoving element {0} from heap", ei);
//h.display();
e = edge[ei];
uSet = partition.findSet(e.u);
vSet = partition.findSet(e.v);
if(uSet != vSet)
{
partition.union(uSet, vSet);
mst[i++] = e;
wgt_sum += e.wgt;
}
}
Console.WriteLine("Weight of MST is: {0}", wgt_sum);
return mst;
}
/**********************************************************
*
* Kruskal's minimum spanning tree algorithm
*
**********************************************************/
public Edge[] MST_Kruskal()
{
int ei, i = 0;//i tracks the current position in the mst array
Edge e;
int uSet, vSet;//unused
UnionFindSets partition;
// create edge array to store MST
// Initially it has no edges.
mst = new Edge[V - 1];
// priority queue for indices of array of edges
Edge[] sorted = sortEdges();
// create partition of singleton sets for the vertices
partition = new UnionFindSets(V);
partition.showSets();//at this point, each vertex will be in its own set
foreach (Edge cur in sorted)
{
if (partition.valid(cur))//if the current edge wouldn't create a cycle
{
mst[i++] = cur;//add the edge to the mst
partition.unionByEdge(cur);//union the sets of the two vertices in the current edge
}
if (partition.spanning())//if a spanning tree has been formed, the work is complete
{
break;
}
}
partition.showSets();//all the vertices will now be in the same set
return mst;
}
/**********************************************************
*
* Kruskal's minimum spanning tree algorithm
*
**********************************************************/
public Edge[] MST_Kruskal()
{
int i = 0;//i tracks the current position in the mst array
UnionFindSets partition;
// create edge array to store MST
// Initially it has no edges.
mst = new Edge[V - 1];
// priority queue for indices of array of edges
Edge[] sorted = sortEdges();
// create partition of singleton sets for the vertices
partition = new UnionFindSets(V);
Console.WriteLine("\nSets before creating MST:");
partition.showSets();//at this point, each vertex will be in its own set
foreach (Edge cur in sorted)
{
if (partition.valid(cur))//if the current edge wouldn't create a cycle
{
mst[i++] = cur;//add the edge to the mst
partition.unionByEdge(cur);//union the sets of the two vertices in the current edge
//outputting information about the current step to the console
Console.Write("\nAdded ");
cur.show();
Console.Write("\nCurrent contents of sets:\n");
partition.showSets();
}
if (partition.spanning())//if a spanning tree has been formed, the work is complete
{
Console.Write("\nMinimum Spanning Tree has been formed\n");
break;
}
}
Console.WriteLine("\nSets after creating MST:");
partition.showSets();//all the vertices will now be in the same set
return mst;
}
