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Given a set of $m$ points and a set of $n$ lines in the plane, we consider the problem of computing the faces of the arrangement of the lines that contain at least one point. In this paper, we present an $O(m^{2/3}n^{2/3}+(n+m)\log n)$ time…

Computational Geometry · Computer Science 2026-03-06 Haitao Wang

The number of triangulations of a planar n point set is known to be $c^n$, where the base $c$ lies between $2.43$ and $30.$ The fastest known algorithm for counting triangulations of a planar n point set runs in $O^*(2^n)$ time. The fastest…

Computational Geometry · Computer Science 2014-11-21 Marek Karpinski , Andrzej Lingas , Dzmitry Sledneu

In this paper, we consider the problem of determining in polynomial time whether a given planar point set $P$ of $n$ points admits 4-connected triangulation. We propose a necessary and sufficient condition for recognizing $P$, and present…

Computational Geometry · Computer Science 2013-10-08 Ajit Arvind Diwan , Subir Kumar Ghosh , Bodhayan Roy

Visual object counting is a fundamental computer vision task in industrial inspection, where accurate, high-throughput inventory tracking and quality assurance are critical. Moreover, manufactured parts are often too light to reliably…

Computer Vision and Pattern Recognition · Computer Science 2026-03-17 Corentin Dumery , Noa Etté , Aoxiang Fan , Ren Li , Jingyi Xu , Hieu Le , Pascal Fua

Vassilevska and Williams (STOC 2009) showed how to count simple paths on $k$ vertices and matchings on $k/2$ edges in an $n$-vertex graph in time $n^{k/2+O(1)}$. In the same year, two different algorithms with the same runtime were given by…

Data Structures and Algorithms · Computer Science 2015-08-17 Andreas Björklund , Petteri Kaski , Łukasz Kowalik

The (non-uniform) sparsest cut problem is the following graph-partitioning problem: given a "supply" graph, and demands on pairs of vertices, delete some subset of supply edges to minimize the ratio of the supply edges cut to the total…

Data Structures and Algorithms · Computer Science 2021-06-01 Vincent Cohen-Addad , Anupam Gupta , Philip N. Klein , Jason Li

A data structure is presented for point location in connected planar subdivisions when the distribution of queries is known in advance. The data structure has an expected query time that is within a constant factor of optimal. More…

Computational Geometry · Computer Science 2013-03-12 Sebastien Collette , Vida Dujmovic , John Iacono , Stefan Langerman , Pat Morin

We consider the fundamental problems of approximately counting the numbers of edges and triangles in a graph in sublinear time. Previous algorithms for these tasks are significantly more efficient under a promise that the arboricity of the…

Data Structures and Algorithms · Computer Science 2025-09-25 Talya Eden , Ronitt Rubinfeld , Arsen Vasilyan

The Max-Cut problem is known to be NP-hard on general graphs, while it can be solved in polynomial time on planar graphs. In this paper, we present a fixed-parameter tractable algorithm for the problem on `almost' planar graphs: Given an…

Data Structures and Algorithms · Computer Science 2019-05-27 Yasuaki Kobayashi , Yusuke Kobayashi , Shuichi Miyazaki , Suguru Tamaki

We study the classical scheduling problem on parallel machines %with precedence constraints where the precedence graph has the bounded depth $h$. Our goal is to minimize the maximum completion time. We focus on developing approximation…

Data Structures and Algorithms · Computer Science 2023-02-02 Bin Fu , Yumei Huo , Hairong Zhao

We study the Multiple Cluster Scheduling problem and the Multiple Strip Packing problem. For both problems, there is no algorithm with approximation ratio better than $2$ unless $P = NP$. In this paper, we present an algorithm with…

Data Structures and Algorithms · Computer Science 2019-02-12 Klaus Jansen , Malin Rau

We consider the problem of counting the copies of a length-$k$ pattern $\sigma$ in a sequence $f \colon [n] \to \mathbb{R}$, where a copy is a subset of indices $i_1 < \ldots < i_k \in [n]$ such that $f(i_j) < f(i_\ell)$ if and only if…

Data Structures and Algorithms · Computer Science 2025-10-27 Omri Ben-Eliezer , Slobodan Mitrović , Pranjal Srivastava

Let $P$ be a set of $n$ points in the plane. A crossing-free structure on $P$ is a plane graph with vertex set $P$. Examples of crossing-free structures include triangulations of $P$, spanning cycles of $P$, also known as polygonalizations…

Computational Geometry · Computer Science 2013-12-18 Victor Alvarez , Karl Bringmann , Radu Curticapean , Saurabh Ray

We investigate the complexity of algorithms counting ones in different sets of operations. With addition and logical operations (but no shift) $O(\log^2(n))$ steps suffice to count ones. Parity can be computed with complexity $O(\log(n))$,…

Computational Complexity · Computer Science 2015-07-03 Holger Petersen

We prove that any oblivious algorithm using space $S$ to find the median of a list of $n$ integers from $\{1,...,2n\}$ requires time $\Omega(n \log\log_S n)$. This bound also applies to the problem of determining whether the median is odd…

Computational Complexity · Computer Science 2015-05-04 Paul Beame , Vincent Liew , Mihai Pǎtraşcu

We consider the Minimum Steiner Cut problem on undirected planar graphs with non-negative edge weights. This problem involves finding the minimum cut of the graph that separates a specified subset $X$ of vertices (terminals) into two parts.…

Data Structures and Algorithms · Computer Science 2020-01-01 Stephen Jue , Philip N. Klein

We consider the classical makespan minimization scheduling problem where $n$ jobs must be scheduled on $m$ identical machines. Using weighted random sampling, we developed two sublinear time approximation schemes: one for the case where $n$…

Data Structures and Algorithms · Computer Science 2026-05-05 Bin Fu , Yumei Huo , Hairong Zhao

We provide a randomized linear time approximation scheme for a generic problem about clustering of binary vectors subject to additional constrains. The new constrained clustering problem encompasses a number of problems and by solving it,…

Data Structures and Algorithms · Computer Science 2018-07-20 Fedor V. Fomin , Petr A. Golovach , Daniel Lokshtanov , Fahad Panolan , Saket Saurabh

Detecting polygons defined by a set of line segments in a plane is an important step in analyzing vector drawings. This paper presents an approach combining several algorithms to detect basic polygons from arbitrary line segments. The…

Computational Geometry · Computer Science 2023-12-29 Alfredo Ferreira , Manuel J. Fonseca , Joaquim A. Jorge

Many modern applications use computer vision to detect and count objects in massive image collections. However, when the detection task is very difficult or in the presence of domain shifts, the counts may be inaccurate even with…

Computer Vision and Pattern Recognition · Computer Science 2023-06-07 Gustavo Perez , Subhransu Maji , Daniel Sheldon
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