Sudoku is a popular newspaper puzzle that has become an international phenomenon. Sudoku which means “single digits” is a logicbased combinatorial puzzle with rules that are quite simple. Several algorithms have been used to solve this combinatorial optimization problem. This paper explores the possibility of using the Artificial Bee Colony (ABC) algorithm, a relatively new swarm-based optimiza...

Insight problem solving is characterized by restructuring. We hypothesized that the difficulty of rebus puzzles could be manipulated by systematically varying the restructurings required to solve them. An experiment using rebus puzzles varied the number of restructurings (one or two) required to solve a problem and the level at which the restructuring took place (sub-word level, word level, and...

Recently, edge matching puzzles, an NP-complete problem, have received, thanks to money-prized contests, considerable attention from wide audiences. We consider these competitions not only a challenge for SAT/CSP solving techniques but also as an opportunity to showcase the advances in the SAT/CSP community to a general audience. This paper studies the NP-complete problem of edge matching puzzl...

Client puzzles have been proposed as a mechanism for proving legitimate intentions by providing “proofs of work”, which can be applied to discourage malicious usage of resources. A typical problem of puzzle constructions is the difference in expected solving time on different computing platforms. We call puzzles which can be solved independently of client computing resources fair client puzzles...

Sudoku is a very simple and well-known puzzle that has achieved international popularity in the recent past. This paper addresses the problem of encoding Sudoku puzzles into conjunctive normal form (CNF), and subsequently solving them using polynomial-time propositional satisfiability (SAT) inference techniques. We introduce two straightforward SAT encodings for Sudoku: the minimal encoding and...

Rebus puzzles and compound remote associate problems have been successfully used to study problem solving. These problems are physically compact, often can be solved within short time limits, and have unambiguous solutions, and English versions have been normed for solving rates and levels of difficulty. Many studies on problem solving with sudden insight have taken advantage of these features ...

Amazons is a young board game with simple rules and a high branching factor, which makes it a suitable test-bed for planning research. This paper considers the computational complexity of amazons puzzles and restricted amazons endgames. We rst prove the NP{ completeness of the Hamilton circuit problem for cubic subgraphs of the integer grid. This result is then used to show that solving amazons...

What determines difficulty of solving a problem? Although this question has been studied before, we found examples which show large differences in problem difficulty which are not explained by concepts identified in previous research. This differences are caused mainly by the structure of a problems’ state spaces and cannot be easily captured by static metrics like size of the state space or th...

The paper addresses a gap in the educational curriculum for engineers by proposing a new course that aims at getting engineering students to think about how to frame and solve unstructured problems. The idea is to increase the student’s mathematical awareness and problem-solving skills by discussing a variety of puzzles. The paper makes an argument that this approach – called Puzzle-Based Learn...