A 3.3904-Competitive Online Algorithm for List Update with Uniform Costs

Abstract

We consider the List Update problem where the cost of each swap is assumed to be 1. This is in contrast to the ``standard'' model, in which an algorithm is allowed to swap the requested item with previous items for free. We construct an online algorithm Full-Or-Partial-Move (FPM), whose competitive ratio is at most $3.3904$, improving over the previous best known bound of $4$.