Rikudo is NP-complete
Discrete Mathematics
2021-01-26 v1 Computational Complexity
Abstract
Rikudo is a number-placement puzzle, where the player is asked to complete a Hamiltonian path on a hexagonal grid, given some clues (numbers already placed and edges of the path). We prove that the game is complete for NP, even if the puzzle has no hole. When all odd numbers are placed it is in P, whereas it is still NP-hard when all numbers of the form are placed.
Cite
@article{arxiv.2101.09332,
title = {Rikudo is NP-complete},
author = {Viet-Ha Nguyen and Kévin Perrot},
journal= {arXiv preprint arXiv:2101.09332},
year = {2021}
}