A Simple Mergeable Dictionary

A mergeable dictionary is a data structure storing a dynamic subset S of a totally ordered set U and supporting predecessor searches in S. Apart from insertions and deletions to S, we can both merge two arbitrarily interleaved dictionaries and split a given dictionary around some pivot x ∈ U . We present an implementation of a mergeable dictionary matching the optimal amortized logarithmic bounds of Iacono and Özkan [11]. However, our solution is significantly simpler. The proposed data structure can also be generalized to the case when the universe U is dynamic or infinite, thus addressing one issue of [11]. 1998 ACM Subject Classification F.2.2 Nonnumerical Algorithms and Problems, E.1 Data Structures