"Peg solitaire is a board game for one player involving movement of pegs on a board with holes. Some sets use marbles in a board with indentations. The game is known simply as Solitaire in the United Kingdom where the card games are called Patience. It is also referred to as Brainvita (especially in India) ...", quoted from Wikipedia article Peg-Solitaire.

This clojure application finds solutions for the game of peg solitaire. For a small number of moves all constellations are determined iteratively and stored in an internal hash-map. Hashing ensures that each board setup is evaluated only once. After an iteration step the given solution space is pruned by means of a scoring function. The next iteration step is applied only for those constellations which seem to be most promising afterwards. This approach shrinks the number of analyzed constellations dramatically. On a 2 GHz Intel Dual Core machine the solution is determined in only 20 seconds.

You need the clojure build tool leinignen for compilation. Download the lein script file from Github

$ cd ~/bin
$ wget http://github.com/technomancy/leiningen/raw/stable/bin/lein
$ chmod +x lein

and type

$ lein self-install

The following commands will generate and stand-alone jar file:

$ lein compile
$ lein uberjar

Refer also to Zef's Leiningen page for more specific information about build options.

The following command will start the simulation

$ java -jar solitaire-standalone.jar 

Two optional parameters allow to change the complexity of the solution space. The first determines the number of iterations before pruning takes place. The second one determines the number of constellations to be taken into account for following iterations

This clojure solitaire solver implementation stands under the terms of the GNU General Public Licence.

September 2011, Otto Linnemann

Thanks to all the giants whose shoulders we stand on. And the giants theses giants stand on... And special thanks to Rich Hickey (and the team) for Clojure. Really, thanks!

• Clojure: http://clojure.org
• Leiningen: https://github.com/technomancy/leiningen