An approximation algorithm for the k-level capacitated facility location problem
Journal of Combinatorial Optimization
A primal-dual approximation algorithm for the k-level stochastic facility location problem
AAIM'10 Proceedings of the 6th international conference on Algorithmic aspects in information and management
Optimal content placement for a large-scale VoD system
Proceedings of the 6th International COnference
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Approximation algorithms for the Fault-Tolerant Facility Placement problem
Information Processing Letters
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Discrete Applied Mathematics
Fast bounding procedures for large instances of the Simple Plant Location Problem
Computers and Operations Research
Inapproximability of the multi-level uncapacitated facility location problem
Proceedings of the twenty-third annual ACM-SIAM symposium on Discrete Algorithms
Black-box reductions for cost-sharing mechanism design
Proceedings of the twenty-third annual ACM-SIAM symposium on Discrete Algorithms
Improved approximation algorithms for the robust fault-tolerant facility location problem
Information Processing Letters
An approximation algorithm for the k-level stochastic facility location problem
Operations Research Letters
Improved LP-rounding approximation algorithm for k-level uncapacitated facility location
ICALP'12 Proceedings of the 39th international colloquium conference on Automata, Languages, and Programming - Volume Part I
Approximation Algorithms for Capacitated Location Routing
Transportation Science
A cross-monotonic cost-sharing scheme for the concave facility location game
Journal of Global Optimization
Approximation Algorithms for Integrated Distribution Network Design Problems
INFORMS Journal on Computing
Improved approximation algorithms for constrained fault-tolerant resource allocation
FCT'13 Proceedings of the 19th international conference on Fundamentals of Computation Theory
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We obtain a 1.5-approximation algorithm for the metric uncapacitated facility location (UFL) problem, which improves on the previously best known 1.52-approximation algorithm by Mahdian, Ye, and Zhang. Note that the approximability lower bound by Guha and Khuller is $1.463\dots$. An algorithm is a ($\lambda_f$,$\lambda_c$)-approximation algorithm if the solution it produces has total cost at most $\lambda_f\cdot F^*+\lambda_c\cdot C^*$, where $F^*$ and $C^*$ are the facility and the connection cost of an optimal solution. Our new algorithm, which is a modification of the $(1+2/e)$-approximation algorithm of Chudak and Shmoys, is a $(1.6774,1.3738)$-approximation algorithm for the UFL problem and is the first one that touches the approximability limit curve $(\gamma_f,1+2e^{-\gamma_f})$ established by Jain, Mahdian, and Saberi. As a consequence, we obtain the first optimal approximation algorithm for instances dominated by connection costs. When combined with a $(1.11,1.7764)$-approximation algorithm proposed by Jain et al., and later analyzed by Mahdian et al., we obtain the overall approximation guarantee of 1.5 for the metric UFL problem. We also describe how to use our algorithm to improve the approximation ratio for the 3-level version of UFL.