On the Stack-Size of General Tries

نویسندگان

  • Jérémie Bourdon
  • Markus E. Nebel
  • Brigitte Vallée
چکیده

Digital trees or tries are a general purpose flexible data structure that implements dictionaries built on words. The present paper is focussed on the average-case analysis of an important parameter of this tree-structure, i.e., the stack-size. The stack-size of a tree is the memory needed by a storage-optimal preorder traversal. The analysis is carried out under a general model in which words are produced by a source (in the information-theoretic sense) that emits symbols. Under some natural assumptions that encompass all commonly used data models (and more), we obtain a precise average-case and probabilistic analysis of stack-size. Furthermore, we study the dependency between the stack-size and the ordering on symbols in the alphabet: we establish that, when the source emits independent symbols, the optimal ordering arises when the most probable symbol is the last one in this order. Mathematics Subject Classification. 68P05, 68W40, 94A15.

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عنوان ژورنال:
  • ITA

دوره 35  شماره 

صفحات  -

تاریخ انتشار 2001