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Computing a shortest path between two nodes in an undirected unweighted graph is among the most basic algorithmic tasks. Breadth first search solves this problem in linear time, which is clearly also a lower bound in the worst case.…

Data Structures and Algorithms · Computer Science 2023-08-01 Noga Alon , Allan Grønlund , Søren Fuglede Jørgensen , Kasper Green Larsen

We present a very simple and intuitive algorithm to find balanced sparse cuts in a graph via shortest-paths. Our algorithm combines a new multiplicative-weights framework for solving unit-weight multi-commodity flows with standard ball…

Data Structures and Algorithms · Computer Science 2022-09-20 Li Chen , Rasmus Kyng , Maximilian Probst Gutenberg , Sushant Sachdeva

We devise an algorithm that approximately computes the number of paths of length $k$ in a given directed graph with $n$ vertices up to a multiplicative error of $1 \pm \varepsilon$. Our algorithm runs in time $\varepsilon^{-2} 4^k(n+m)…

Data Structures and Algorithms · Computer Science 2018-04-26 Cornelius Brand , Holger Dell , Thore Husfeldt

We give the first almost-linear total time algorithm for deciding if a flow of cost at most $F$ still exists in a directed graph, with edge costs and capacities, undergoing decremental updates, i.e., edge deletions, capacity decreases, and…

Data Structures and Algorithms · Computer Science 2024-07-16 Jan van den Brand , Li Chen , Rasmus Kyng , Yang P. Liu , Simon Meierhans , Maximilian Probst Gutenberg , Sushant Sachdeva

We consider the classical Minimum Balanced Cut problem: given a graph $G$, compute a partition of its vertices into two subsets of roughly equal volume, while minimizing the number of edges connecting the subsets. We present the first {\em…

Data Structures and Algorithms · Computer Science 2020-05-05 Julia Chuzhoy , Yu Gao , Jason Li , Danupon Nanongkai , Richard Peng , Thatchaphol Saranurak

We present improved deterministic algorithms for approximating shortest paths in the Congested Clique model of distributed computing. We obtain $poly(\log\log n)$-round algorithms for the following problems in unweighted undirected…

Data Structures and Algorithms · Computer Science 2020-03-09 Michal Dory , Merav Parter

We study the 2-Disjoint Shortest Paths (2-DSP) problem: given a directed weighted graph and two terminal pairs $(s_1,t_1)$ and $(s_2,t_2)$, decide whether there exist vertex-disjoint shortest paths between each pair. Building on recent…

Data Structures and Algorithms · Computer Science 2025-10-09 Keerti Choudhary , Amit Kumar , Lakshay Saggi

In this note, we study the expander decomposition problem in a more general setting where the input graph has positively weighted edges and nonnegative demands on its vertices. We show how to extend the techniques of Chuzhoy et al. (FOCS…

Data Structures and Algorithms · Computer Science 2021-06-04 Jason Li , Thatchaphol Saranurak

In this paper, we study the \textsf{Planar Disjoint Paths} problem: Given an undirected planar graph $G$ with $n$ vertices and a set $T$ of $k$ pairs $(s_i,t_i)_{i=1}^k$ of vertices, the goal is to find a set $\mathcal P$ of $k$ pairwise…

Data Structures and Algorithms · Computer Science 2022-11-09 Kyungjin Cho , Eunjin Oh , Seunghyeok Oh

In the vertex connectivity problem, given an undirected $n$-vertex $m$-edge graph $G$, we need to compute the minimum number of vertices that can disconnect $G$ after removing them. This problem is one of the most well-studied graph…

Data Structures and Algorithms · Computer Science 2022-10-26 Thatchaphol Saranurak , Sorrachai Yingchareonthawornchai

introduce {\sc Planar Disjoint Paths Completion}, a completion counterpart of the Disjoint Paths problem, and study its parameterized complexity. The problem can be stated as follows: given a, not necessarily connected, plane graph $G,$ $k$…

Data Structures and Algorithms · Computer Science 2015-11-18 Isolde Adler , Stavros G. Kolliopoulos , Dimitrios M. Thilikos

The disjoint paths problem is a fundamental problem in algorithmic graph theory and combinatorial optimization. For a given graph $G$ and a set of $k$ pairs of terminals in $G$, it asks for the existence of $k$ vertex-disjoint paths…

Combinatorics · Mathematics 2020-11-23 William Lochet

Given an undirected graph and two disjoint vertex pairs $s_1,t_1$ and $s_2,t_2$, the Shortest two disjoint paths problem (S2DP) asks for the minimum total length of two vertex disjoint paths connecting $s_1$ with $t_1$, and $s_2$ with…

Data Structures and Algorithms · Computer Science 2018-06-21 Andreas Björklund , Thore Husfeldt

(see paper for full abstract) We show that the Edge-Disjoint Paths problem is W[1]-hard parameterized by the number $k$ of terminal pairs, even when the input graph is a planar directed acyclic graph (DAG). This answers a question of…

Data Structures and Algorithms · Computer Science 2021-01-27 Rajesh Chitnis

We consider the computational problem of finding short paths in the skeleton of the perfect matching polytope of a bipartite graph. We prove that unless $P=NP$, there is no polynomial-time algorithm that computes a path of constant length…

Optimization and Control · Mathematics 2022-10-27 Jean Cardinal , Raphael Steiner

Let $G$ be a directed planar graph of complexity $n$, each arc having a nonnegative length. Let $s$ and $t$ be two distinct faces of $G$; let $s_1,...,s_k$ be vertices incident with $s$; let $t_1,...,t_k$ be vertices incident with $t$. We…

Data Structures and Algorithms · Computer Science 2008-02-21 Eric Colin De Verdière , Alexander Schrijver

Let G be a graph with minimum degree $\delta$. It is well-known that maximal adjacency orderings (MAOs) compute a vertex set S such that every pair of S is connected by at least $\delta$ internally vertex-disjoint paths in G. We present an…

Discrete Mathematics · Computer Science 2016-09-22 Johanna E. Preißer , Jens M. Schmidt

We present a combinatorial algorithm for computing exact maximum flows in directed graphs with $n$ vertices and edge capacities from $\{1,\dots,U\}$ in $n^{2+o(1)}\log U$ time, which is almost optimal in dense graphs. Our algorithm is a…

Data Structures and Algorithms · Computer Science 2025-09-30 Aaron Bernstein , Joakim Blikstad , Thatchaphol Saranurak , Ta-Wei Tu

We provide new tradeoffs between approximation and running time for the decremental all-pairs shortest paths (APSP) problem. For undirected graphs with $m$ edges and $n$ nodes undergoing edge deletions, we provide four new approximate…

Data Structures and Algorithms · Computer Science 2024-04-30 Michal Dory , Sebastian Forster , Yasamin Nazari , Tijn de Vos

In the decremental single-source shortest paths (SSSP) problem, the input is an undirected graph $G=(V,E)$ with $n$ vertices and $m$ edges undergoing edge deletions, together with a fixed source vertex $s\in V$. The goal is to maintain a…

Data Structures and Algorithms · Computer Science 2020-09-21 Julia Chuzhoy , Thatchaphol Saranurak