Addressing NP-Complete Puzzles with Monte-Carlo Methods

NP-complete problems are a challenging task for researchers, who investigate tractable versions and attempt to generalise the methods used for solving them. Over the years a large set of successful standard methods have been developed. We mention A* and IDA* which have proven to be reasonably successful in solving a set of NP-complete problems, particularly single-agent games (puzzles). However, sometimes these methods do not work well. The intriguing question then is whether there are new methods that will help us out. In this paper we investigate whether Monte-Carlo Tree-Search (MCTS) is an interesting alternative. We propose a new MCTS variant, called Single-Player Monte-Carlo Tree-Search (SP-MCTS). Our domain of research is the puzzle SameGame. It turned out that our SP-MCTS program gained the highest scores so far on the standardised test set. So, SP-MCTS can be considered as a new method for addressing NP-complete puzzles successfully.