Simplified Self-Adapting Skip Lists

The Simplified Self-Adapting Skip List, a practical new extension of the Skip List data structure, is designed for use with data that exhibit bias, that is, a nonuniform distribution of queries to set elements. The structure observes an initially unknown degree of bias in queries to a data set and adapts itself to a consistently nearly-optimal configuration, improving search efficiency and speed. By modifying the original Skip List design in intuitive ways, self-optimization is achieved while maintaining an extreme simplicity of description, implementation, and operation unmatched by previous dynamic Skip Lists. The additional memory, time, and conceptual overheads introduced by this structure over the original Skip List are considerably less than in previous dynamic designs, but search speed is comparable or superior, making the SSASL better suited than its predecessors for operations in which time or memory efficiency is critical.