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We describe a $O(\log n )$-approximation algorithm for computing the homotopic \Frechet distance between two polygonal curves that lie on the boundary of a triangulated topological disk. Prior to this work, algorithms were known only for…

Computational Geometry · Computer Science 2015-09-02 Sariel Har-Peled , Amir Nayyeri , Mohammad Salavatipour , Anastasios Sidiropoulos

Let G be an input graph with n vertices and m edges and let k be a fixed parameter. We provide a single exponential FPT algorithm with running time O(c^kn(n+m)), c= min {18,k} that turns graph G into an interval graph by deleting at most k…

Data Structures and Algorithms · Computer Science 2016-02-09 Arash Rafiey

Computing the Fr\'echet distance between two polygonal curves takes roughly quadratic time. In this paper, we show that for a special class of curves the Fr\'echet distance computations become easier. Let $P$ and $Q$ be two polygonal curves…

Computational Geometry · Computer Science 2019-08-28 Joachim Gudmundsson , Majid Mirzanezhad , Ali Mohades , Carola Wenk

The Fr\'echet distance is a commonly used distance measure for curves. Computing the Fr\'echet distance between two polygonal curves of $n$ vertices takes roughly quadratic time, and conditional lower bounds suggest that approximating to…

Computational Geometry · Computer Science 2025-05-09 Thijs van der Horst , Marc van Kreveld , Tim Ophelders , Bettina Speckmann

Let $P$ be a polygon with $k$ vertices. Let $R$ and $B$ be two simple, interior disjoint curves on the boundary of $P$, with $n$ and $m$ vertices. We show how to compute the Fr\'echet distance between $R$ and $B$ using the geodesic…

Computational Geometry · Computer Science 2025-04-21 Thijs van der Horst , Marc van Kreveld , Tim Ophelders , Bettina Speckmann

A flipturn is an operation that transforms a nonconvex simple polygon into another simple polygon, by rotating a concavity 180 degrees around the midpoint of its bounding convex hull edge. Joss and Shannon proved in 1973 that a sequence of…

The Fr\'echet distance is a popular similarity measure that is well-understood for polygonal curves in $\mathbb{R}^d$: near-quadratic time algorithms exist, and conditional lower bounds suggest that these results cannot be improved…

Computational Geometry · Computer Science 2025-05-09 Thijs van der Horst , Marc van Kreveld , Tim Ophelders , Bettina Speckmann

We revisit a standard polygon containment problem: given a convex $k$-gon $P$ and a convex $n$-gon $Q$ in the plane, find a placement of $P$ inside $Q$ under translation and rotation (if it exists), or more generally, find the largest copy…

Computational Geometry · Computer Science 2024-03-21 Timothy M. Chan , Isaac M. Hair

We provide a spectrum of new theoretical insights and practical results for finding a Minimum Dilation Triangulation (MDT), a natural geometric optimization problem of considerable previous attention: Given a set $P$ of $n$ points in the…

Computational Geometry · Computer Science 2025-02-26 Sándor P. Fekete , Phillip Keldenich , Michael Perk

Let $P$ and $Q$ be two simple polygons in the plane of total complexity $n$, each of which can be decomposed into at most $k$ convex parts. We present an $(1-\varepsilon)$-approximation algorithm, for finding the translation of $Q$, which…

Computational Geometry · Computer Science 2014-06-24 Sariel Har-Peled , Subhro Roy

We study the problem of computing the minimum area triangle that circumscribes a given $n$-sided convex polygon touching edge-to-edge. In other words, we compute the minimum area triangle that is the intersection of 3 half-planes out of $n$…

Computational Geometry · Computer Science 2022-08-15 Kai Jin , Zhiyi Huang

We study the problem of finding a triangulation T of a planar point set S such as to minimize the expected distance between two points x and y chosen uniformly at random from S. By distance we mean the length of the shortest path between x…

Computational Geometry · Computer Science 2012-06-21 Laszlo Kozma

In the $k$-Cut problem, we are given an edge-weighted graph $G$ and an integer $k$, and have to remove a set of edges with minimum total weight so that $G$ has at least $k$ connected components. Prior work on this problem gives, for all $h…

Data Structures and Algorithms · Computer Science 2017-10-25 Anupam Gupta , Euiwoong Lee , Jason Li

The potato-peeling problem (also known as convex skull) is a fundamental computational geometry problem and the fastest algorithm to date runs in $O(n^8)$ time for a polygon with $n$ vertices that may have holes. In this paper, we consider…

Computational Geometry · Computer Science 2019-06-25 Loïc Crombez , Guilherme D. da Fonseca , Yan Gérard

Let $P\subset\mathbb{R}^{2}$ be a set of $n$ points. In this paper we show two new algorithms, one to compute the number of triangulations of $P$, and one to compute the number of pseudo-triangulations of $P$. We show that our algorithms…

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

This article is about measuring and visualizing distances between domino tilings. Given two tilings of a simply connected square tiled surface, we're interested in the minimum number of flips between two tilings. Given a certain shape,…

Combinatorics · Mathematics 2016-08-26 Hugo Parlier , Samuel Zappa

Let $P$ be a convex polyhedron and $Q$ be a convex polygon with $n$ vertices in total in three-dimensional space. We present a deterministic algorithm that finds a translation vector $v \in \mathbb{R}^3$ maximizing the overlap area $|P \cap…

Computational Geometry · Computer Science 2025-01-28 Hyuk Jun Kweon , Honglin Zhu

Given two convex polygons $P$ and $Q$ with $n$ and $m$ edges, the maximum overlap problem is to find a translation of $P$ that maximizes the area of its intersection with $Q$. We give the first randomized algorithm for this problem with…

Computational Geometry · Computer Science 2025-04-28 Timothy M. Chan , Isaac M. Hair

In this paper, we consider the following $k$-dispersion problem. Given a set $S$ of $n$ points placed in the plane in a convex position, and an integer $k$ ($0<k<n$), the objective is to compute a subset $S'\subset S$ such that $|S'|=k$ and…

Computational Geometry · Computer Science 2022-05-05 Vishwanath R. Singireddy , Manjanna Basappa

Given is a 1.5D terrain $\mathcal{T}$, i.e., an $x$-monotone polygonal chain in $\mathbb{R}^2$. For a given $2\le k\le n$, our objective is to approximate the largest area or perimeter convex polygon of exactly or at most $k$ vertices…

Computational Geometry · Computer Science 2022-06-07 Vahideh Keikha