Prim, Kruskal Why? only undirected graph?

Why Can’t Prim’s or Kruskal’s Algorithms Be Used on a Directed Graph? | Baeldung on Computer ScienceBaeldung on Computer Science

In our example, there is just one MSA possible. That is . But running Kruskal’s algorithm, we first of all select :

Since this edge is not contained in our MSA it is impossible to construct one from the Kruskal algorithm in this example.

3.2. Prim

For the Prim algorithm, we have a similar setup:

This time the only possible MSA is . Prim’s algorithm starts at a random node, in this case, . It then takes the edge with the lowest edge connected to , which is the node to :

Since the edge, is not contained in the only MSA that the following steps won’t generate an MSA for this example.