License: Creative Commons Attribution 3.0 Unported license (CC BY 3.0)
When quoting this document, please refer to the following
DOI: 10.4230/LIPIcs.FUN.2016.2
URN: urn:nbn:de:0030-drops-58796
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Almanza, Matteo ; Leucci, Stefano ; Panconesi, Alessandro

Trainyard is NP-hard

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Recently, due to the widespread diffusion of smart-phones, mobile puzzle games have experienced a huge increase in their popularity. A successful puzzle has to be both captivating and challenging, and it has been suggested that this features are somehow related to their computational complexity. Indeed, many puzzle games - such as Mah-Jongg, Sokoban, Candy Crush, and 2048, to name a few - are known to be NP-hard.

In this paper we consider Trainyard: a popular mobile puzzle game whose goal is to get colored trains from their initial stations to suitable destination stations. We prove that the problem of determining whether there exists a solution to a given Trainyard level is NP. We also provide an implementation of our hardness reduction (see

BibTeX - Entry

  author =	{Matteo Almanza and Stefano Leucci and Alessandro Panconesi},
  title =	{{Trainyard is NP-hard}},
  booktitle =	{8th International Conference on Fun with Algorithms (FUN 2016)},
  pages =	{2:1--2:14},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-005-7},
  ISSN =	{1868-8969},
  year =	{2016},
  volume =	{49},
  editor =	{Erik D. Demaine and Fabrizio Grandoni},
  publisher =	{Schloss Dagstuhl--Leibniz-Zentrum fuer Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{},
  URN =		{urn:nbn:de:0030-drops-58796},
  doi =		{10.4230/LIPIcs.FUN.2016.2},
  annote =	{Keywords: Complexity of Games, Trainyard}

Keywords: Complexity of Games, Trainyard
Collection: 8th International Conference on Fun with Algorithms (FUN 2016)
Issue Date: 2016
Date of publication: 02.06.2016

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