New algorithms on wavelet trees and applications to information retrieval

T Gagie, G Navarro, SJ Puglisi - Theoretical Computer Science, 2012 - Elsevier
Wavelet trees are widely used in the representation of sequences, permutations, text
collections, binary relations, discrete points, and other succinct data structures. We show …

Counting inversions, offline orthogonal range counting, and related problems

TM Chan, M Pătraşcu - Proceedings of the twenty-first annual ACM-SIAM …, 2010 - SIAM
We give an-time algorithm for counting the number of inversions in a permutation on n
elements. This improves a long-standing previous bound of O (n lg n/lg lg n) that followed …

Range quantile queries: Another virtue of wavelet trees

T Gagie, SJ Puglisi, A Turpin - International Symposium on String …, 2009 - Springer
We show how to use a balanced wavelet tree as a data structure that stores a list of numbers
and supports efficient range quantile queries. A range quantile query takes a rank and the …

Range selection and median: Tight cell probe lower bounds and adaptive data structures

AG Jørgensen, KG Larsen - Proceedings of the Twenty-Second Annual ACM …, 2011 - SIAM
Range selection is the problem of preprocessing an input array A of n unique integers, such
that given a query (i, j, k), one can report the k'th smallest integer in the subarray A [i], A [i+ …

Towards optimal range medians

GS Brodal, B Gfeller, AG Jørgensen… - Theoretical Computer …, 2011 - Elsevier
We consider the following problem: Given an unsorted array of n elements, and a sequence
of intervals in the array, compute the median in each of the subarrays defined by the …

Linear-space data structures for range mode query in arrays

TM Chan, S Durocher, KG Larsen, J Morrison… - Theory of Computing …, 2014 - Springer
A mode of a multiset S is an element a∈ S of maximum multiplicity; that is, a occurs at least
as frequently as any other element in S. Given an array A 1: n of n elements, we consider a …

Adaptive and approximate orthogonal range counting

TM Chan, BT Wilkinson - ACM Transactions on Algorithms (TALG), 2016 - dl.acm.org
We present three new results on one of the most basic problems in geometric data
structures, 2-D orthogonal range counting. All the results are in the w-bit word RAM model …

Data structures for range median queries

GS Brodal, AG Jørgensen - International Symposium on Algorithms and …, 2009 - Springer
In this paper we design data structures supporting range median queries, ie report the
median element in a sub-range of an array. We consider static and dynamic data structures …

Linear-space data structures for range mode query in arrays

TM Chan, S Durocher, KG Larsen, J Morrison… - STACS'12 (29th …, 2012 - hal.science
A mode of a multiset S is an element a in S of maximum multiplicity; that is, a occurs at least
as frequently as any other element in S. Given an array A [1: n] of n elements, we consider a …

Linear-space data structures for range frequency queries on arrays and trees

S Durocher, R Shah, M Skala, SV Thankachan - Algorithmica, 2016 - Springer
We present O (n) O (n)-space data structures to support various range frequency queries on
a given array A 0: n-1 A 0: n-1 or tree TT with nn nodes. Given a query consisting of an …