Directed Paths with Few or Many Colors in Colored Directed Graphs∗
نویسندگان
چکیده
Given a graph D = (V (D), A(D)) and a coloring of D, not necessarily a proper coloring of either the arcs or the vertices of D, we consider the complexity of finding a path of D from a given vertex s to another given vertex t with as few different colors as possible, and of finding one with as many different colors as possible. We show that the first problem is polynomial-time solvable, and that the second problem is NP-hard.
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