In the topological sort algorithm, why is it important that the graph be acyclic? What would our topological Sort() method do if given a cyclic graph? In our representation, each undirected edge is...

In the topological sort algorithm, why is it important that the graph be acyclic? What would our topological Sort() method do if given a cyclic graph?

In our representation, each undirected edge is represented by two directed edges. Why do these excess edges not cause a problem for Kruskal ’s algorithm?