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In this paper we propose a graph-based data clustering algorithm which is based on exact clustering of a minimum spanning tree in terms of a minimum isoperimetry criteria. We show that our basic clustering algorithm runs in $O(n \log n)$…

Computer Vision and Pattern Recognition · Computer Science 2012-03-20 Amir Daneshgar , Ramin Javadi , Basir Shariat Razavi

In binary jumbled pattern matching we wish to preprocess a binary string $S$ in order to answer queries $(i,j)$ which ask for a substring of $S$ that is of size $i$ and has exactly $j$ 1-bits. The problem naturally generalizes to…

Data Structures and Algorithms · Computer Science 2014-07-01 Danny Hermelin , Gad M. Landau , Yuri Rabinovich , Oren Weimann

We introduce the lazy search tree data structure. The lazy search tree is a comparison-based data structure on the pointer machine that supports order-based operations such as rank, select, membership, predecessor, successor, minimum, and…

Data Structures and Algorithms · Computer Science 2020-10-20 Bryce Sandlund , Sebastian Wild

The problem of Text Indexing is a fundamental algorithmic problem in which one wishes to preprocess a text in order to quickly locate pattern queries within the text. In the ever evolving world of dynamic and on-line data, there is also a…

Data Structures and Algorithms · Computer Science 2012-08-21 Tsvi Kopelowitz

Offering rich contexts to Large Language Models (LLMs) has shown to boost the performance in various tasks, but the resulting longer prompt would increase the computational cost and might exceed the input limit of LLMs. Recently, some…

Computation and Language · Computer Science 2025-09-30 Wenhao Mao , Chengbin Hou , Tianyu Zhang , Xinyu Lin , Ke Tang , Hairong Lv

Extractive compression is a challenging natural language processing problem. This work contributes by formulating neural extractive compression as a parse tree transduction problem, rather than a sequence transduction task. Motivated by…

Information Retrieval · Computer Science 2018-09-26 Davide Bacciu , Antonio Bruno

The problem of storing a set of strings --- a string dictionary --- in compact form appears naturally in many cases. While classically it has represented a small part of the whole data to be processed (e.g., for Natural Language processing…

Data Structures and Algorithms · Computer Science 2011-01-31 Nieves R. Brisaboa , Rodrigo Cánovas , Miguel A. Martínez-Prieto , Gonzalo Navarro

In this paper we study the fundamental problem of maintaining a dynamic collection of strings under the following operations: concat - concatenates two strings, split - splits a string into two at a given position, compare - finds the…

Data Structures and Algorithms · Computer Science 2016-04-11 Paweł Gawrychowski , Adam Karczmarz , Tomasz Kociumaka , Jakub Łącki , Piotr Sankowski

The well-known dictionary-based algorithms of the Lempel-Ziv (LZ) 77 family are the basis of several universal lossless compression techniques. These algorithms are asymmetric regarding encoding/decoding time and memory requirements, with…

Data Structures and Algorithms · Computer Science 2009-12-31 Artur Ferreira , Arlindo Oliveira , Mario Figueiredo

Efficiently word storing and searching is an important task in computer science. An application space complexity, time complexity, and overall performance depend on this string data. Many word searching data structures and algorithms exist…

Data Structures and Algorithms · Computer Science 2019-11-06 Rahat Yeasin Emon , Sharmistha Chanda Tista

The block tree [Belazzougui et al., J. Comput. Syst. Sci. '21] is a compressed representation of a length-$n$ text that supports access, rank, and select queries while requiring only $O(z\log\frac{n}{z})$ words of space, where $z$ is the…

Data Structures and Algorithms · Computer Science 2025-12-30 Robert Clausecker , Florian Kurpicz , Etienne Palanga

We study the problem of enumerating the answers to a query formulated in monadic second order logic (MSO) over an unranked forest F that is compressed by a straight-line program (SLP) D. Our main result states that this can be done after…

Formal Languages and Automata Theory · Computer Science 2026-03-17 Markus Lohrey , Markus L. Schmid

Despite their high accuracy, complex neural networks demand significant computational resources, posing challenges for deployment on resource constrained devices such as mobile phones and embedded systems. Compression algorithms have been…

Machine Learning · Computer Science 2025-09-23 Ali Aghababaei-Harandi , Massih-Reza Amini

Detecting all the strings that occur in a text more frequently or less frequently than expected according to an IID or a Markov model is a basic problem in string mining, yet current algorithms are based on data structures that are either…

Data Structures and Algorithms · Computer Science 2015-08-13 Djamal Belazzougui , Fabio Cunial

Park et al. [TCS 2020] observed that the similarity between two (numerical) strings can be captured by the Cartesian trees: The Cartesian tree of a string is a binary tree recursively constructed by picking up the smallest value of the…

Data Structures and Algorithms · Computer Science 2022-04-18 Tsubasa Oizumi , Takeshi Kai , Takuya Mieno , Shunsuke Inenaga , Hiroki Arimura

String attractors [STOC 2018] are combinatorial objects recently introduced to unify all known dictionary compression techniques in a single theory. A set $\Gamma\subseteq [1..n]$ is a $k$-attractor for a string $S\in[1..\sigma]^n$ if and…

Data Structures and Algorithms · Computer Science 2020-12-09 Dominik Kempa , Alberto Policriti , Nicola Prezza , Eva Rotenberg

The Block Tree is a recently proposed data structure that reaches compression close to Lempel-Ziv while supporting efficient direct access to text substrings. In this paper we show how a self-index can be built on top of a Block Tree so…

Data Structures and Algorithms · Computer Science 2017-10-11 Gonzalo Navarro

We present an algorithm for computing a maximum agreement subtree of two unrooted evolutionary trees. It takes O(n^{1.5} log n) time for trees with unbounded degrees, matching the best known time complexity for the rooted case. Our…

Computational Engineering, Finance, and Science · Computer Science 2007-05-23 Ming-Yang Kao , Tak-Wah Lam , Wing-Kin Sung , Hing-Fung Ting

Let $S$ be a string of length $n$ over an alphabet $\Sigma$ and let $Q$ be a subset of $\Sigma$ of size $q \geq 2$. The 'co-occurrence problem' is to construct a compact data structure that supports the following query: given an integer $w$…

Data Structures and Algorithms · Computer Science 2022-11-11 Philip Bille , Inge Li Gørtz , Tord Stordalen

Big data, encompassing extensive datasets, has seen rapid expansion, notably with a considerable portion being textual data, including strings and texts. Simple compression methods and standard data structures prove inadequate for…

Data Structures and Algorithms · Computer Science 2024-11-11 Takaaki Nishimoto , Yasuo Tabei