Computational Complexity and an Integer Programming Model of Shakashaka
Author(s)Demaine, Erik D.; Okamoto, Yoshio; Uehara, Ryuhei; Uno, Yushi
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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.
DepartmentMassachusetts Institute of Technology. Computer Science and Artificial Intelligence Laboratory; Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science
IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences
Institute of Electronics, Information and Communications Engineers
Demaine, Erik D., Yoshio Okamoto, Ryuhei Uehara, and Yushi Uno. “Computational Complexity and an Integer Programming Model of Shakashaka.” IEICE Trans. Fundamentals E97.A, no. 6 (2014): 1213–1219.
Author's final manuscript