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Given a simple polygon $P$ consisting of $n$ vertices, we study the problem of designing space-efficient algorithms for computing (i) the visibility polygon of a point inside $P$, (ii) the weak visibility polygon of a line segment inside…

Computational Geometry · Computer Science 2012-04-13 Minati De , Anil Maheshwari , Subhas C. Nandy

We propose an algorithm with expected complexity of $\bigO(n\log n)$ arithmetic operations to solve a special shortest vector problem arising in computer-and-forward design, where $n$ is the dimension of the channel vector. This algorithm…

Information Theory · Computer Science 2016-02-02 Jinming Wen , Xiao-Wen Chang

We prove that for an arbitrarily small constant $\eps>0,$ assuming NP$\not \subseteq$DTIME$(2^{{\log^{O(1/\eps)} n}})$, the preprocessing versions of the closest vector problem and the nearest codeword problem are hard to approximate within…

Computational Complexity · Computer Science 2011-09-13 Subhash Khot , Preyas Popat , Nisheeth K. Vishnoi

Consider a sliding camera that travels back and forth along an orthogonal line segment $s$ inside an orthogonal polygon $P$ with $n$ vertices. The camera can see a point $p$ inside $P$ if and only if there exists a line segment containing…

Computational Geometry · Computer Science 2013-10-01 Stephane Durocher , Omrit Filtser , Robert Fraser , Ali Mehrabi , Saeed Mehrabi

Clustering with capacity constraints is a fundamental problem that attracted significant attention throughout the years. In this paper, we give the first FPT constant-factor approximation algorithm for the problem of clustering points in a…

Data Structures and Algorithms · Computer Science 2024-02-21 Sayan Bandyapadhyay , William Lochet , Saket Saurabh

We present a quantum interior-point method (IPM) for second-order cone programming (SOCP) that runs in time $\widetilde{O} \left( n\sqrt{r} \frac{\zeta \kappa}{\delta^2} \log \left(1/\epsilon\right) \right)$ where $r$ is the rank and $n$…

Quantum Physics · Physics 2021-04-14 Iordanis Kerenidis , Anupam Prakash , Dániel Szilágyi

The fundamental sparsest cut problem takes as input a graph $G$ together with the edge costs and demands, and seeks a cut that minimizes the ratio between the costs and demands across the cuts. For $n$-node graphs~$G$ of treewidth~$k$,…

Data Structures and Algorithms · Computer Science 2024-04-23 Parinya Chalermsook , Matthias Kaul , Matthias Mnich , Joachim Spoerhase , Sumedha Uniyal , Daniel Vaz

We present algorithms for the $(1+\epsilon)$-approximate version of the closest vector problem for certain norms. The currently fastest algorithm (Dadush and Kun 2016) for general norms has running time of $2^{O(n)} (1/\epsilon)^n$. We…

Data Structures and Algorithms · Computer Science 2021-11-03 Márton Naszódi , Moritz Venzin

We present several algorithms for computing the visibility polygon of a simple polygon $P$ from a viewpoint inside the polygon, when the polygon resides in read-only memory and only few working variables can be used. The first algorithm…

Computational Geometry · Computer Science 2013-04-09 Luis Barba , Matias Korman , Stefan Langerman , Rodrigo I. Silveira

Let $\mathcal{S}$ be a connected planar polygonal subdivision with $n$ edges that we want to preprocess for point-location queries, and where we are given the probability $\gamma_i$ that the query point lies in a polygon $P_i$ of…

Computational Geometry · Computer Science 2016-04-20 Boris Aronov , Mark de Berg , David Eppstein , Marcel Roeloffzen , Bettina Speckmann

Boxicity of a graph G(V, E) is the minimum integer k such that G can be represented as the intersection graph of axis parallel boxes in $\mathbb{R}^k$. Cubicity is a variant of boxicity, where the axis parallel boxes in the intersection…

Discrete Mathematics · Computer Science 2015-06-09 Abhijin Adiga , Jasine Babu , L. Sunil Chandran

We consider the classical Minimum Crossing Number problem: given an $n$-vertex graph $G$, compute a drawing of $G$ in the plane, while minimizing the number of crossings between the images of its edges. This is a fundamental and extensively…

Data Structures and Algorithms · Computer Science 2022-02-15 Julia Chuzhoy , Zihan Tan

We consider the Minimum Convex Partition problem: Given a set P of n points in the plane, draw a plane graph G on P, with positive minimum degree, such that G partitions the convex hull of P into a minimum number of convex faces. We show…

Computational Geometry · Computer Science 2021-12-22 Nicolas Grelier

We present an $\mathcal{O}^\star(2^{0.5n})$ time and $\mathcal{O}^\star(2^{0.249999n})$ space randomized algorithm for solving worst-case Subset Sum instances with $n$ integers. This is the first improvement over the long-standing…

Data Structures and Algorithms · Computer Science 2021-04-13 Jesper Nederlof , Karol Węgrzycki

We study the allocation problem in the Massively Parallel Computation (MPC) model. This problem is a special case of $b$-matching, in which the input is a bipartite graph with capacities greater than $1$ in only one part of the bipartition.…

Data Structures and Algorithms · Computer Science 2025-06-06 Jakub Łącki , Slobodan Mitrović , Srikkanth Ramachandran , Wen-Horng Sheu

We study the Euclidean minimum weight perfect matching problem for $n$ points in the plane. It is known that any deterministic approximation algorithm whose approximation ratio depends only on $n$ requires at least $\Omega(n \log n)$ time.…

Computational Geometry · Computer Science 2026-01-09 Stefan Hougardy , Karolina Tammemaa

We study optimization problems that are neither approximable in polynomial time (at least with a constant factor) nor fixed parameter tractable, under widely believed complexity assumptions. Specifically, we focus on Maximum Independent…

Data Structures and Algorithms · Computer Science 2008-10-29 Marek Cygan , Lukasz Kowalik , Marcin Pilipczuk , Mateusz Wykurz

The (unweighted) point-separation problem asks, given a pair of points $s$ and $t$ in the plane, and a set of candidate geometric objects, for the minimum-size subset of objects whose union blocks all paths from $s$ to $t$. Recent work has…

Computational Geometry · Computer Science 2026-02-16 Jayson Lynch , Jack Spalding-Jamieson

Many streaming algorithms provide only a high-probability relative approximation. These two relaxations, of allowing approximation and randomization, seem necessary -- for many streaming problems, both relaxations must be employed…

Data Structures and Algorithms · Computer Science 2023-05-16 Vladimir Braverman , Robert Krauthgamer , Aditya Krishnan , Shay Sapir

The computation of (i) $\varepsilon$-kernels, (ii) approximate diameter, and (iii) approximate bichromatic closest pair are fundamental problems in geometric approximation. In this paper, we describe new algorithms that offer significant…

Computational Geometry · Computer Science 2017-04-03 Sunil Arya , Guilherme D. da Fonseca , David M. Mount