Approximation Algorithms for Metric Facility Location Problems

Local Search Based Approximation Algorithms for Two-Stage Stochastic Location Problems

We present a nested local search algorithm to approximate several variants of metric two-stage stochastic facility location problems. These problems are generalizations of the well-studied metric uncapacitated facility location problem, taking uncertainties in demand values and costs into account. The proposed nested local search procedure uses three facility operations: adding, dropping, and s...

Improved Approximation Algorithms for Metric Facility Location Problems

Approximation Methods for Solving the Equitable Location Problem with Probabilistic Customer Behavior

Location-allocation of facilities in service systems is an essential factor of their performance. One of the considerable situations which less addressed in the relevant literature is to balance service among customers in addition to minimize location-allocation costs. This is an important issue, especially in the public sector. Reviewing the recent researches in this field shows that most of t...

Primal-Dual Approximation Algorithms for Metric Facility Location and k-Median Problems

We present approximation algorithms for the metric uncapacitated facility location problem and the metric k-median problem achieving guarantees of 3 and 6 respectively. The distinguishing feature of our algorithms is their low running time: O(m log m) and O(m logm(L+log(n))) respectively, where n and m are the total number of vertices and edges in the underlying graph. The main algorithmic idea...

Near-Constant-Time Distributed Algorithms on a Congested Clique

This paper presents constant-time and near-constant-time distributed algorithms for a variety of problems in the congested clique model. We show how to compute a 3-ruling set in expected O(log log logn) rounds and using this, we obtain a constant-approximation to metric facility location, also in expected O(log log logn) rounds. In addition, assuming an input metric space of constant doubling d...