Off-line algorithms for the list update problem

Abstract

Optimum off-line algorithms for the list update problem are investigated. The list update problem involves implementing a dictionary of items as a linear list. Several characterizations of optimum algorithms are given; these lead to optimum algorithm which runs in time Θ2 n ( n − 1)! m, where n is the length of the list and m is the number of requests. The previous best algorithm, an adaptation of a more general algorithm due to Manasse et al. (1988), runs in time Θ( n!) 2 m.