5 papers
Tetris is Hard with Just One Piece Type
MIT Hardness Group, Josh Brunner, Erik D. Demaine +2
We analyze the computational complexity of Tetris clearing (determining whether the player can clear an initial board using a given sequence of pieces) and survival (determining wh…
Undecidability of Tiling with a Tromino
ULB CompGeom Group, Zachary Abel, Hugo Akitaya +6
Given a periodic placement of copies of a tromino (either L or I), we prove co-RE-completeness (and hence undecidability) of deciding whether it can be completed to a plane tiling.…
Pushing Blocks without Fixed Walls via Checkable Gizmos: Push-1 is PSPACE-Complete
MIT Hardness Group, Josh Brunner, Lily Chung +4
We prove PSPACE-completeness of Push-1: given a rectangular grid of 1 x 1 cells, each possibly occupied by a movable block, can a robot move from one specified location to another,…
ASP-Completeness of Hamiltonicity in Grid Graphs, with Applications to Loop Puzzles
MIT Hardness Group, Josh Brunner, Lily Chung +4
We prove that Hamiltonicity in maximum-degree-3 grid graphs (directed or undirected) is ASP-complete, i.e., it has a parsimonious reduction from every NP search problem (including…
Complexity of Planar Graph Orientation Consistency, Promise-Inference, and Uniqueness, with Applications to Minesweeper Variants
MIT Hardness Group, Della Hendrickson, Andy Tockman
We study three problems related to the computational complexity of the popular game Minesweeper. The first is consistency: given a set of clues, is there any arrangement of mines t…