2022-080

About Depth-First Search (DFS) and topological sorting, consider the following statements:

1. The visited node order for the following graph and adjacency lists, starting with s, is s a c e b d
   
2. While running a DFS on a directed graph, if from vertex u we visit a finished vertex v, then the edge (u, v) is a cross-edge
3. If a topological sort exists for the vertices in a directed graph, then a DFS on the graph will produce no back edges 
4. A DFS in a directed graph always produces the same number of tree edges 
5. Suppose we perform a DFS on a directed graph G. If we remove all the back edges found, the resulting graph is acyclic 

Which alternative lists all false statements and no true statement among I-V?

1. I, II, III
2. II, IV
3. I, III, IV, V
4. II
5. None of the above

Original Idea by: Levy Chaves