CS4335 Tutorial 13
Question 1: The vertex cover problem is as follows: Given a graph G=(V, E), find
a subset V'⊆V with minimum number of vertices such that for each edge (u, v)∈E at
least one of u and v is in V’. Give a ratio-2 approximation algorithm.
Question 2: (Center selection Problem) Given a set of points V in the plane, find k
points c1, c2, .., ck in the plane (not necessarily in V) such that for each v in V,
min i=1, 2, …, k d(v, ci)  d and d is minimized. Give a ratio-2 approximation
algorithm. (See Section 11.2 in the text book.)