Given a directed graph with vertices colored yellow, red, or orange, identifies all the yellow vertices that can reach an orange vertex along a path that contains no other yellow vertices (the graph is with e edges and v vertices and v <= e <= v^2).

Indicate whether

a) if this problem is NP-Hard or

b) Identify the smallest values k and l such that there is an O(e^k v^l poly(log(e), log(v))) algorithm for this problem.)