The steiner problem with edge lengths 1 and 2,
Information Processing Letters
Proof verification and the hardness of approximation problems
Journal of the ACM (JACM)
Improved Steiner tree approximation in graphs
SODA '00 Proceedings of the eleventh annual ACM-SIAM symposium on Discrete algorithms
Complexity and Approximation: Combinatorial Optimization Problems and Their Approximability Properties
Introduction to Algorithms
Hi-index | 0.00 |
In this paper, we consider an interesting variant of the well-known Steiner tree problem: Given a complete graph G = (V,E) with a cost function c:E →R+ and two subsets R and R′ satisfying R′⊂R⊆V, a selected-internal Steiner tree is a Steiner tree which contains (or spans) all the vertices in R such that each vertex in R′ cannot be a leaf. The selected-internal Steiner tree problem is to find a selected-internal Steiner tree with the minimum cost. In this paper, we show that the problem is MAX SNP-hard even when the costs of all edges in the input graph are restricted to either 1 or 2. We also present an approximation algorithm for the problem.