Carrying is Hard: Exploring the Gap between Hardness for NP and PSPACE for the Hanano and Jelly no Puzzles

Fuente: arXiv
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Hauptverfasser: Chavrimootoo, Michael C., Youn, Jin Seok
Format: Preprint
Veröffentlicht: 2026
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author Chavrimootoo, Michael C.
Youn, Jin Seok
author_facet Chavrimootoo, Michael C.
Youn, Jin Seok
contents The Hanano Puzzle is a one-player game with irreversible gravity, where the goal is to make colored blocks make contact with flowers of the corresponding color. The game Jelly no Puzzle shares similar mechanics. In general, determining if a given level of each of the two games is solvable is PSPACE-complete. There are also known restrictions under which determining if a level of Jelly no Puzzle is solvable is NP-complete. We find that under the same restrictions, determining if a level of Hanano Puzzle is solvable remains PSPACE-complete. We thus study several restrictions on Hanano, contrast them with known results about Jelly no Puzzle, and posit that the mechanism at the heart of the PSPACE-hardness is the ability for blocks to carry each other.
format Preprint
id arxiv_https___arxiv_org_abs_2601_08057
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Carrying is Hard: Exploring the Gap between Hardness for NP and PSPACE for the Hanano and Jelly no Puzzles
Chavrimootoo, Michael C.
Youn, Jin Seok
Computational Complexity
The Hanano Puzzle is a one-player game with irreversible gravity, where the goal is to make colored blocks make contact with flowers of the corresponding color. The game Jelly no Puzzle shares similar mechanics. In general, determining if a given level of each of the two games is solvable is PSPACE-complete. There are also known restrictions under which determining if a level of Jelly no Puzzle is solvable is NP-complete. We find that under the same restrictions, determining if a level of Hanano Puzzle is solvable remains PSPACE-complete. We thus study several restrictions on Hanano, contrast them with known results about Jelly no Puzzle, and posit that the mechanism at the heart of the PSPACE-hardness is the ability for blocks to carry each other.
title Carrying is Hard: Exploring the Gap between Hardness for NP and PSPACE for the Hanano and Jelly no Puzzles
topic Computational Complexity
url https://arxiv.org/abs/2601.08057