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We propose a new kind of sliding-block puzzle, called Gourds, where the objective is to rearrange 1 x 2 pieces on a hexagonal grid board of 2n + 1 cells with n pieces, using sliding, turning and pivoting moves. This puzzle has a single…

Data Structures and Algorithms · Computer Science 2020-11-03 Joep Hamersma , Marc van Kreveld , Yushi Uno , Tom C. van der Zanden

Wordle is a single-player word-guessing game where the goal is to discover a secret word $w$ that has been chosen from a dictionary $D$. In order to discover $w$, the player can make at most $\ell$ guesses, which must also be words from…

Computational Complexity · Computer Science 2022-05-17 Daniel Lokshtanov , Bernardo Subercaseaux

We investigate the complexity of a puzzle that turns out to be NL-complete.

Computational Complexity · Computer Science 2015-07-13 Holger Petersen

Poset games are a class of combinatorial game that remain unsolved. Soltys and Wilson proved that computing wining strategies is in \textbf{PSPACE} and aside from special cases such as Nim and N-Free games, \textbf{P} time algorithms for…

Combinatorics · Mathematics 2021-01-26 Alexander Clow , Stephen Finbow

The Honey-Bee game is a two-player board game that is played on a connected hexagonal colored grid or (in a generalized setting) on a connected graph with colored nodes. In a single move, a player calls a color and thereby conquers all the…

Computer Science and Game Theory · Computer Science 2011-02-16 Rudolf Fleischer , Gerhard J. Woeginger

We analyze the computational complexity of optimally playing the two-player board game Push Fight, generalized to an arbitrary board and number of pieces. We prove that the game is PSPACE-hard to decide who will win from a given position,…

Computational Complexity · Computer Science 2018-03-13 Jeffrey Bosboom , Erik D. Demaine , Mikhail Rudoy

The Bulgarian solitaire is a mathematical card game played by one person. A pack of n cards is divided into several decks (or "piles"). Each move consists of the removing of one card from each deck and collecting the removed cards to form a…

Combinatorics · Mathematics 2015-03-04 Vesselin Drensky

Connect Four is a two-player game where each player attempts to be the first to create a sequence of four of their pieces, arranged horizontally, vertically, or diagonally, by dropping pieces into the columns of a grid of width seven and…

Combinatorics · Mathematics 2025-02-18 Robert Steele , Daniel B. Larremore

Peg solitaire is a game generalized to connected graphs by Beeler and Hoilman. In the game pegs are placed on all but one vertex. If $xyz$ form a 3-vertex path and $x$ and $y$ each have a peg but $z$ does not, then we can remove the pegs at…

Combinatorics · Mathematics 2014-03-03 Jennifer Wise , Sarah Loeb

The Parks Puzzle is a paper-and-pencil puzzle game that is classically played on a square grid with different colored regions (the parks). The player needs to place a certain number of "trees" in each row, column, and park such that none…

Computational Complexity · Computer Science 2024-11-05 Igor Minevich , Gabe Cunningham , Aditya Karan , Joshua V. Gyllinsky

Many popular puzzle and matching games have been analyzed through the lens of computational complexity. Prominent examples include Sudoku, Candy Crush, and Flood-It. A common theme among these widely played games is that their generalized…

Computational Complexity · Computer Science 2026-03-03 Linus Klocker , Simon D. Fink

The New York Times (NYT) games have found widespread popularity in recent years and reportedly account for an increasing fraction of the newspaper's readership. In this paper, we bring the computational lens to the study of New York Times…

Computational Complexity · Computer Science 2025-09-16 Alessandro Giovanni Alberti , Flavio Chierichetti , Mirko Giacchini , Daniele Muscillo , Alessandro Panconesi , Erasmo Tani

Various forms of sorting problems have been studied over the years. Recently, two kinds of sorting puzzle apps are popularized. In these puzzles, we are given a set of bins filled with colored units, balls or water, and some empty bins.…

We prove that king chasing problem in Chinese Chess is NP-hard when generalized to $n\times n$ boards. `King chasing' is a frequently-used strategy in Chinese Chess, which means that the player has to continuously check the opponent in…

Combinatorics · Mathematics 2026-04-03 Chao Li , Zhujun Zhang , Chao Yang

In combinatorial game theory, the winning player for a position in normal play is analyzed and characterized via algebraic operations. Such analyses define a value for each position, called a game value. A game (ruleset) is called universal…

Discrete Mathematics · Computer Science 2023-10-04 Kanae Yoshiwatari , Hironori Kiya , Koki Suetsugu , Tesshu Hanaka , Hirotaka Ono

A poset game is a two-player game played over a partially ordered set (poset) in which the players alternate choosing an element of the poset, removing it and all elements greater than it. The first player unable to select an element of the…

Computational Complexity · Computer Science 2015-03-20 Daniel Grier

It is odd that chess grandmasters often disagree in their analysis of positions, sometimes even of simple ones, and that a grandmaster can hold his own against an powerful analytic machine such as Deep Blue. The fact that there must exist…

Computational Complexity · Computer Science 2007-05-23 M. Chaves

We solve the problem of one-dimensional peg solitaire. In particular, we show that the set of configurations that can be reduced to a single peg forms a regular language, and that a linear-time algorithm exists for reducing any…

Combinatorics · Mathematics 2007-05-23 Cristopher Moore , David Eppstein

In this paper, we give a formal definition of the popular word-guessing game Wordle. We show that, in general, determining if a given Wordle instance admits a winning strategy is NP-complete. We also show that given a Wordle instance of…

Computational Complexity · Computer Science 2022-04-11 Will Rosenbaum

We study the problem of checking for the existence of constrained pure Nash equilibria in a subclass of polymatrix games defined on weighted directed graphs. The payoff of a player is defined as the sum of nonnegative rational weights on…

Computer Science and Game Theory · Computer Science 2016-11-30 Sunil Simon , Dominik Wojtczak