Rank-Sensitive Data Structures

Output-sensitive data structures result from preprocessing n items and are capable of reporting the items satisfying an on-line query in O(t(n) + ℓ) time, where t(n) is the cost of traversing the structure and ℓ ≤ n is the number of reported items satisfying the query. In this paper we focus on rank-sensitive data structures, which are additionally given a ranking of the n items, so that just the top k best-ranking items should be reported at query time, sorted in rank order, at a cost of O(t(n) + k) time. Note that k is part of the query as a parameter under the control of the user (as opposed to ℓ which is query-dependent). We explore the problem of adding rank-sensitivity to data structures such as suffix trees or range trees, where the ℓ items satisfying the query form O(polylog(n)) intervals of consecutive entries from which we choose the top k best-ranking ones. Letting s(n) be the number of items (including their copies) stored in the original data structures, we incre...

• Type: Conference
• Year: 2005
• Where: SPIRE
• Authors: Iwona Bialynicka-Birula, Roberto Grossi
• Keywords: Data Structures, Output-sensitive Data Structures, Rank-sensitive Data Structures, SPIRE 2005