Wataridori is NP-Complete

Suthee Ruangwises

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arXiv · 2601.09345

Wataridori is NP-Complete

Suthee Ruangwises

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Abstract

Wataridori is a pencil puzzle that involves drawing paths in a rectangular grid to connect circles into pairs while satisfying several constraints. In this paper, we prove that deciding whether a given Wataridori puzzle has a solution is NP-complete via a reduction from Numberlink, another pencil puzzle that has previously been proved NP-complete.

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Suthee Ruangwises. 2026-01-14. Wataridori is NP-Complete. https://arxiv.org/abs/2601.09345

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