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In the $k$-mismatch problem we are given a pattern of length $n$ and a text and must find all locations where the Hamming distance between the pattern and the text is at most $k$. A series of recent breakthroughs have resulted in an…

Data Structures and Algorithms · Computer Science 2021-06-22 Paweł Gawrychowski , Tatiana Starikovskaya

We consider the problem of pattern matching with $k$ mismatches, where there can be don't care or wild card characters in the pattern. Specifically, given a pattern $P$ of length $m$ and a text $T$ of length $n$, we want to find all…

Data Structures and Algorithms · Computer Science 2016-10-31 Marius Nicolae , Sanguthevar Rajasekaran

We revisit the complexity of one of the most basic problems in pattern matching. In the k-mismatch problem we must compute the Hamming distance between a pattern of length m and every m-length substring of a text of length n, as long as…

Data Structures and Algorithms · Computer Science 2015-08-28 Raphaël Clifford , Allyx Fontaine , Ely Porat , Benjamin Sach , Tatiana Starikovskaya

In the problem of $\texttt{Generalised Pattern Matching}\ (\texttt{GPM})$ [STOC'94, Muthukrishnan and Palem], we are given a text $T$ of length $n$ over an alphabet $\Sigma_T$, a pattern $P$ of length $m$ over an alphabet $\Sigma_P$, and a…

Data Structures and Algorithms · Computer Science 2020-01-20 Bartłomiej Dudek , Paweł Gawrychowski , Tatiana Starikovskaya

We investigate the generalisation of quantum search of unstructured and totally ordered sets to search of partially ordered sets (posets). Two models for poset search are considered. In both models, we show that quantum algorithms can…

Quantum Physics · Physics 2009-06-18 Ashley Montanaro

Countless variants of the Lempel-Ziv compression are widely used in many real-life applications. This paper is concerned with a natural modification of the classical pattern matching problem inspired by the popularity of such compression…

Data Structures and Algorithms · Computer Science 2011-04-22 Pawel Gawrychowski

We consider the problem of finding \textit{semi-matching} in bipartite graphs which is also extensively studied under various names in the scheduling literature. We give faster algorithms for both weighted and unweighted case. For the…

Data Structures and Algorithms · Computer Science 2012-06-15 Jittat Fakcharoenphol , Bundit Laekhanukit , Danupon Nanongkai

In the subset sum problem we are given n positive integers along with a target integer t. A solution is a subset of these integers summing to t. In this short note we show that for a given subset sum instance there is a proof of size…

Computational Complexity · Computer Science 2016-02-05 Jesper Nederlof

We give a quantum algorithm to find the index y in a table T of size N such that in time O(c sqrt N), T[y] is minimum with probability at least 1-1/2^c.

Quantum Physics · Physics 2008-02-03 Christoph Durr , Peter Hoyer

Let $t$ be a permutation (that shall play the role of the {\em text}) on $[n]$ and a pattern $p$ be a sequence of $m$ distinct integer(s) of $[n]$, $m\leq n$. The pattern $p$ occurs in $t$ in position $i$ if and only if $p_1... p_m$ is…

Data Structures and Algorithms · Computer Science 2013-04-29 Djamal Belazzougui , Adeline Pierrot , Mathieu Raffinot , Stéphane Vialette

The task of finding an entry in an unsorted list of $N$ elements famously takes $O(N)$ queries to an oracle for a classical computer and $O(\sqrt{N})$ queries for a quantum computer using Grover's algorithm. Reformulated as a spatial search…

Quantum Physics · Physics 2022-01-04 Thomas G. Wong

In the Pattern Masking for Dictionary Matching (PMDM) problem, we are given a dictionary $\mathcal{D}$ of $d$ strings, each of length $\ell$, a query string $q$ of length $\ell$, and a positive integer $z$, and we are asked to compute a…

Data Structures and Algorithms · Computer Science 2024-03-11 Panagiotis Charalampopoulos , Huiping Chen , Peter Christen , Grigorios Loukides , Nadia Pisanti , Solon P. Pissis , Jakub Radoszewski

Given a text $T$ and a pattern $P$ over alphabet $\Sigma$, the classic exact matching problem searches for all occurrences of pattern $P$ in text $T$. Unlike exact matching problem, order-preserving pattern matching (OPPM) considers the…

Data Structures and Algorithms · Computer Science 2017-05-29 Davaajav Jargalsaikhan , Diptarama , Ryo Yoshinaka , Ayumi Shinohara

The Cartesian tree of a sequence captures the relative order of the sequence's elements. In recent years, Cartesian tree matching has attracted considerable attention, particularly due to its applications in time series analysis. Consider a…

Data Structures and Algorithms · Computer Science 2026-02-10 Panagiotis Charalampopoulos , Jonas Ellert , Manal Mohamed

We consider the task of certifying that a random $d$-dimensional subspace $X$ in $\mathbb{R}^n$ is well-spread - every vector $x \in X$ satisfies $c\sqrt{n} \|x\|_2 \leq \|x\|_1 \leq \sqrt{n}\|x\|_2$. In a seminal work, Barak et. al. showed…

Data Structures and Algorithms · Computer Science 2024-05-10 Venkatesan Guruswami , Jun-Ting Hsieh , Prasad Raghavendra

In the paper, we investigate two problems on strings. The first one is the String matching problem, and the second one is the String comparing problem. We provide a quantum algorithm for the String matching problem that uses exponentially…

Quantum Physics · Physics 2023-05-19 Farid Ablayev , Marat Ablayev , Kamil Khadiev , Nailya Salihova , Alexander Vasiliev

An elastic-degenerate string is a sequence of $n$ finite sets of strings of total length $N$, introduced to represent a set of related DNA sequences, also known as a pangenome. The ED string matching (EDSM) problem consists in reporting all…

Data Structures and Algorithms · Computer Science 2022-09-05 Giulia Bernardini , Estéban Gabory , Solon P. Pissis , Leen Stougie , Michelle Sweering , Wiktor Zuba

We present the first $\mathrm{o}(n)$-space polynomial-time algorithm for computing the length of a longest common subsequence. Given two strings of length $n$, the algorithm runs in $\mathrm{O}(n^{3})$ time with $\mathrm{O}\left(\frac{n…

Data Structures and Algorithms · Computer Science 2020-09-21 Masashi Kiyomi , Takashi Horiyama , Yota Otachi

This paper extends the quantum search class of algorithms to the multiple solution case. It is shown that, like the basic search algorithm, these too can be represented as a rotation in an appropriately defined two dimensional vector space.…

Quantum Physics · Physics 2007-05-23 Lov K. Grover

Given a multiset $S$ of $n$ positive integers and a target integer $t$, the Subset Sum problem asks to determine whether there exists a subset of $S$ that sums up to $t$. The current best deterministic algorithm, by Koiliaris and Xu…

Data Structures and Algorithms · Computer Science 2020-01-03 Ce Jin , Hongxun Wu