IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences
Online ISSN : 1745-1337
Print ISSN : 0916-8508
Special Section on Discrete Mathematics and Its Applications
Computational Complexity and an Integer Programming Model of Shakashaka
Erik D. DEMAINEYoshio OKAMOTORyuhei UEHARAYushi UNO
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2014 Volume E97.A Issue 6 Pages 1213-1219

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Abstract

Shakashaka is a pencil-and-paper puzzle proposed by Guten and popularized by the Japanese publisher Nikoli (like Sudoku). We determine the computational complexity by proving that Shakashaka is NP-complete, and furthermore that counting the number of solutions is #P-complete. Next we formulate Shakashaka as an integer-programming (IP) problem, and show that an IP solver can solve every instance from Nikoli's website within a second.

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© 2014 The Institute of Electronics, Information and Communication Engineers
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