Low Redundancy in Dictionaries with O(1) Worst Case Lookup Time
DOI:
https://doi.org/10.7146/brics.v5i28.19434Resumé
A static dictionary is a data structure for storing subsets of a finite universe U, so that membership queries can be answered efficiently. We study this problem in a unit cost RAM model with word size Omega(log |U|), and show that for n-element subsets,constant worst case query time can be obtained using B +O(log log |U|)+o(n) bits of storage, where B = [log2 (|U| / n)]
is the minimum number of bits needed to represent all
such subsets. The solution for dense subsets uses B + O( |U| log log |U| / log |U| ) bits of storage, and supports constant time rank queries. In a dynamic setting, allowing insertions and deletions, our techniques give an O(B) bit space usage.
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Publiceret
1998-01-28
Citation/Eksport
Pagh, R. (1998). Low Redundancy in Dictionaries with O(1) Worst Case Lookup Time. BRICS Report Series, 5(28). https://doi.org/10.7146/brics.v5i28.19434
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