public void MinimumSpanningTreePrim(VertexMST <T> root)
{
foreach (var vertex in vertices.OfType <VertexMST <T> >())
{
vertex.Key = int.MaxValue;
vertex.Predecessor = null;
}
root.Key = 0;
var heap = new MinHeap <VertexMST <T> >(vertices.Count, vertices.OfType <VertexMST <T> >().ToArray());
while (!heap.IsEmpty)
{
//had to call heapify before extract min since it's not a min heap anymore due to the change of keys
//instead of decrease key
heap.Heapify(0);
var min = heap.Extract();
foreach (var edge in edges.Where((e) => e.From.Equals(min) || e.To.Equals(min)))
{
if (edge.To.Equals(min))
{
if (heap.Contains(edge.From as VertexMST <T>) &&
edge.Weight < (edge.From as VertexMST <T>).Key)
{
edge.From.Predecessor = min;
(edge.From as VertexMST <T>).Key = edge.Weight;
}
}
else
{
if (heap.Contains(edge.To as VertexMST <T>) &&
edge.Weight < (edge.To as VertexMST <T>).Key)
{
edge.To.Predecessor = min;
(edge.To as VertexMST <T>).Key = edge.Weight;
}
}
}
}
}
public int CompareTo(VertexMST <T> other)
{
return(Key.CompareTo(other.Key));
}
private void MakeSet(VertexMST <T> vertex)
{
vertex.Rank = 0;
vertex.Parent = vertex;
}