35 citations · 75 across the 13 of their papers we have counts for
14 papers
Local elimination in the traveling salesman problem
William Cook, Keld Helsgaun, Stefan Hougardy +1
Hougardy and Schroeder (WG 2014) proposed a combinatorial technique for pruning the search space in the traveling salesman problem, establishing that, for a given instance, certain…
The Approximation Ratio of the -Opt Heuristic for the Euclidean Traveling Salesman Problem
Ulrich A. Brodowsky, Stefan Hougardy, Xianghui Zhong
The -Opt heuristic is a simple improvement heuristic for the Traveling Salesman Problem. It starts with an arbitrary tour and then repeatedly replaces edges of the tour by $…
A Fast Optimal Double Row Legalization Algorithm
Stefan Hougardy, Meike Neuwohner, Ulrike Schorr
In Placement Legalization, it is often assumed that (almost) all standard cells possess the same height and can therefore be aligned in cell rows, which can then be treated indepen…
The Approximation Ratio of the 2-Opt Heuristic for the Euclidean Traveling Salesman Problem
Ulrich A. Brodowsky, Stefan Hougardy
The 2-Opt heuristic is a simple improvement heuristic for the Traveling Salesman Problem. It starts with an arbitrary tour and then repeatedly replaces two edges of the tour by two…
The Approximation Ratio of the 2-Opt Heuristic for the Metric Traveling Salesman Problem
Stefan Hougardy, Fabian Zaiser, Xianghui Zhong
The 2-Opt heuristic is one of the simplest algorithms for finding good solutions to the metric Traveling Salesman Problem. It is the key ingredient to the well-known Lin-Kernighan…
Hard to Solve Instances of the Euclidean Traveling Salesman Problem
Stefan Hougardy, Xianghui Zhong
The well known conjecture states that the integrality ratio of the subtour LP is at most for metric Traveling Salesman instances. We present a family of Euclidean Trave…