# Puzzle Solver

Last week I posted a new project to Github. It’s called Puzzle Solver. It is a very basic breadth first search solver for board puzzles.

I have a few puzzles from Israel that have the theme of placing tiles on a board in a specific way. I wanted to try and write a program to solve these types of puzzles. It is a bit more complicated than just a recursive search as tiles can be rotated.

The program only solves for the puzzle listed below, but eventually I want to get it to solve arbitrary puzzles by only requiring the pieces, the board size, and a function indicting “valid state”

## Example

(Source: www.thinkinggames.com)

The solution from running the program yielded 4 solutions:

``````Starting
Solution # 1 =
Place [["Star","Bull","Tria"]] at position 0,0
Place [["Yell"],["Tria"],["Squig"]] at position 3,0
Place [["Squig"],["Star"],["Yell"]] at position 4,0
Place [["Squig","Yell","Bull"]] at position 0,1
Place [["Bull"],["Yell"],["Tria"]] at position 0,2
Place [["Tria","Star"]] at position 1,2
Place [["Star","Squig","Bull"]] at position 1,3
Place [["Tria"],["Bull"]] at position 4,3
Place [["Squig","Yell","Star"]] at position 1,4

[ [ 'Star', 'Bull', 'Tria', 'Yell', 'Squig' ],
[ 'Squig', 'Yell', 'Bull', 'Tria', 'Star' ],
[ 'Bull', 'Tria', 'Star', 'Squig', 'Yell' ],
[ 'Yell', 'Star', 'Squig', 'Bull', 'Tria' ],
[ 'Tria', 'Squig', 'Yell', 'Star', 'Bull' ] ]

Solution # 2 =
Place [["Star","Bull","Tria"]] at position 0,0
Place [["Squig"],["Tria"],["Yell"]] at position 3,0
Place [["Yell"],["Star"],["Squig"]] at position 4,0
Place [["Squig","Yell","Bull"]] at position 0,1
Place [["Bull"],["Yell"],["Tria"]] at position 0,2
Place [["Tria","Star"]] at position 1,2
Place [["Star","Squig","Bull"]] at position 1,3
Place [["Tria"],["Bull"]] at position 4,3
Place [["Squig","Yell","Star"]] at position 1,4

[ [ 'Star', 'Bull', 'Tria', 'Squig', 'Yell' ],
[ 'Squig', 'Yell', 'Bull', 'Tria', 'Star' ],
[ 'Bull', 'Tria', 'Star', 'Yell', 'Squig' ],
[ 'Yell', 'Star', 'Squig', 'Bull', 'Tria' ],
[ 'Tria', 'Squig', 'Yell', 'Star', 'Bull' ] ]

Solution # 3 =
Place [["Star"],["Bull"],["Tria"]] at position 0,0
Place [["Squig"],["Yell"],["Bull"]] at position 1,0
Place [["Bull","Yell","Tria"]] at position 2,0
Place [["Tria"],["Star"]] at position 2,1
Place [["Star"],["Squig"],["Bull"]] at position 3,1
Place [["Squig"],["Yell"],["Star"]] at position 4,1
Place [["Yell","Tria","Squig"]] at position 0,3
Place [["Squig","Star","Yell"]] at position 0,4
Place [["Tria","Bull"]] at position 3,4

[ [ 'Star', 'Squig', 'Bull', 'Yell', 'Tria' ],
[ 'Bull', 'Yell', 'Tria', 'Star', 'Squig' ],
[ 'Tria', 'Bull', 'Star', 'Squig', 'Yell' ],
[ 'Yell', 'Tria', 'Squig', 'Bull', 'Star' ],
[ 'Squig', 'Star', 'Yell', 'Tria', 'Bull' ] ]

Solution # 4 =
Place [["Bull"],["Tria"]] at position 0,0
Place [["Tria"],["Yell"],["Bull"]] at position 1,0
Place [["Squig","Yell","Star"]] at position 2,0
Place [["Star","Squig","Bull"]] at position 2,1
Place [["Squig"],["Star"],["Yell"]] at position 0,2
Place [["Tria","Star"]] at position 2,2
Place [["Yell"],["Tria"],["Squig"]] at position 4,2
Place [["Squig","Yell","Bull"]] at position 1,3
Place [["Star","Bull","Tria"]] at position 1,4

[ [ 'Bull', 'Tria', 'Squig', 'Yell', 'Star' ],
[ 'Tria', 'Yell', 'Star', 'Squig', 'Bull' ],
[ 'Squig', 'Bull', 'Tria', 'Star', 'Yell' ],
[ 'Star', 'Squig', 'Yell', 'Bull', 'Tria' ],
[ 'Yell', 'Star', 'Bull', 'Tria', 'Squig' ] ]

------
Found 4 solutions in 1.259 seconds (595885 iterations)...
``````

## Possible Improvements

The algorithm could possibly be improved to prevent symmetric attempts from being attempted again.

The project is currently hard coded for a specific puzzle game, but without much effort it should be able to be abstracted out as an object with overridable functions to specify the board size, pieces, and a “isValid” function which returns true or false on whether the search should continue.