Fast Algorithms for Diameter-Optimally Augmenting Paths and Trees

07/19/2016

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by   Ulrike Große, et al.

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We consider the problem of augmenting an n-vertex graph embedded in a metric space, by inserting one additional edge in order to minimize the diameter of the resulting graph. We present exact algorithms for the cases when (i) the input graph is a path, running in O(n ^3 n) time, and (ii) the input graph is a tree, running in O(n^2 n) time. We also present an algorithm that computes a (1+)-approximation in O(n + 1/^3) time, for paths in R^d, where d is a constant.