We study labelling schemes for X-constrained path problems. Given a graph (V,E) and X ⊆ V , a path is X-constrained if all intermediate vertices avoidX. We study the problem of assigning labels J(x) to vertices so that given {J(x) : x ∈ X} for any X ⊆ V , we can route on the shortest X-constrained path between x, y ∈ X. This problem is motivated by Internet routing, where the presence of routin...

How difficult is it to find a path between two vertices in finite directed graphs whose independence number is bounded by some constant k? The independence number of a graph is the largest number of vertices that can be picked such that there is no edge between any two of them. The complexity of this problem depends on the exact question we ask: Do we only wish to tell whether a path exists? Do...

We consider the problem of finding shortest non-crossing thick paths in a polygonal domain, where a thick path is a Minkowski sum of a usual path and unit disk. We show that in a simple polygon, K shortest paths may be found in optimal O(K(n + K)) time and O(n + K) space. For polygons with holes we show that the problem becomes (weakly) NP-hard even for the case K = 2 and even when the paths ar...

Driven by many applications, in this paper we study the problem of computing the top-k shortest paths from one set of target nodes to another set of target nodes in a graph, namely the top-k shortest path join (KPJ) between two sets of target nodes. While KPJ is an extension of the problem of computing the top-k shortest paths (KSP) between two target nodes, the existing technique by converting...

The k-goal problem is a generalization of the Shortest Path Problem (SPP) in which the task is to solve k SPP problems, such that all the problems share the same start vertex. kGP was introduced to the heuristic search community for building an Incremental Roadmap Spanner technique (Dobson and Bekris 2014), which is a useful construct in motion plannin for robotics. But kGP has many other appli...

In this paper, Shortest Path Design Problem (SPDP) in which the path is incident to all cells is considered. The bi-directional path is one of the known types of configuration of networks for Automated Guided Vehi-cles (AGV).To solve this problem, two algorithms are developed. For each algorithm an Integer Linear Pro-gramming (ILP) is determined. The objective functions of both algorithms are t...

We give an algorithm to compute a (Euclidean) shortest path in a polygon with h holes and a total of n vertices. The algorithm uses O(n) space and requires O(n + h 2 log n) time.

We present an algorithm for computing k-link rectilinear shortest paths among rectilinear obstacles in the plane. We extend the “continuous Dijkstra” paradigm to store the link distance information associated with each propagating “wavefront”. Our algorithm runs in time O(kn log n) and space O(kn), where n is the number of vertices of the obstacles. Previous algorithms for the problem had worst...

In this paper, we discuss the relation of unsplittable shortest path routing (USPR) to other routing schemes and study the approximability of three USPR network planning problems. Given a digraph D = (V,A) and a set K of directed commodities, an USPR is a set of flow paths Φ(s,t), (s, t) ∈ K, such that there exists a metric λ = (λa) ∈ Z+ with respect to which each Φ(s,t) is the unique shortest ...

We consider the following natural “above guarantee” parameterization of the classical Longest Path problem: For given vertices s and t of a graph G, and an integer k, the problem Longest Detour asks for an (s, t)-path in G that is at least k longer than a shortest (s, t)-path. Using insights into structural graph theory, we prove that Longest Detour is fixed-parameter tractable (FPT) on undirec...