Abstract
The fractional knapsack problem is one of the classical problems in combinatorial optimization, which is well understood in the offline setting. However, the corresponding online setting has been handled only briefly in the theoretical computer science literature so far, although it appears in several applications. Even the previously best known guarantee for the competitive ratio was worse than the best known for the integral problem in the popular random order model. We show that there is an algorithm for the online fractional knapsack problem that admits a competitive ratio of \(4.39\). Our result significantly improves over the previously best known competitive ratio of \(9.37\) and surpasses the current best \(6.65\)-competitive algorithm for the integral case. Moreover, our algorithm is deterministic in contrast to the randomized algorithms achieving the results mentioned above.
J. Giliberti—The work was carried out during a virtual internship at MPI for Informatics.
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Notes
- 1.
Items whose size exceeds the capacity of the knapsack can be cut at the knapsack capacity.
- 2.
It can be accomplished in polynomial time by fixing a random (but consistent) tie-breaking between elements of the same value, based for instance on the identifier of the element [5].
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Giliberti, J., Karrenbauer, A. (2021). Improved Online Algorithm for Fractional Knapsack in the Random Order Model. In: Koenemann, J., Peis, B. (eds) Approximation and Online Algorithms. WAOA 2021. Lecture Notes in Computer Science(), vol 12982. Springer, Cham. https://doi.org/10.1007/978-3-030-92702-8_12
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