Ranked Document Selection
Ian Munro, Gonzalo Navarro, Rahul Shah, and Sharma Thankachan.
Let D be a collection of string
documents of n characters in total. The top-k document retrieval
problem} is to preprocess D into a data structure that, given a query
(P,k), can return the k documents of D most relevant to
The relevance of a document d for a pattern P is given by a predefined
ranking function w(P,d).
Linear space and optimal query time solutions already exist for this problem.
In this paper we consider a novel problem, document selection queries,
which aim to report the kth document most relevent to P (instead of
reporting all top-k documents).
We present a data structure using O(n log^e n) space, for any
constant e>0, answering selection queries in time O(log k /
log log n), and a linear-space data structure answering queries in time
O(log k), given the locus node of P in a (generalized) suffix tree of
D. We also prove that it is unlikely that a succinct-space solution for
this problem exists with poly-logarithmic query time.