= Solitaire =

<<TableOfContents>>

== Problem Description ==
Solitaire is a single player game played on a 7x7 board with 2x2 corners omitted. Each position is either full (containing a peg / marble) or empty.   With 'O' representing full positions and '.' representing an empty position, a possible board configuration is:

[[attachment:board1.txt]]

Each turn the player must jump a peg over an existing peg and removed the 'jumped' peg.  For example, numbering the board from the top left, moving peg (4,2) down would give the following board configuration:

[[attachment:board2.txt]]

The task is, given an initial board configuration, find a sequence of the given number of moves.

== Input Format ==
Thirty two facts giving the initial board configuration, each of which is either:

full(X,Y).

or

empty(X,Y).

indicating that position (X,Y) is either full or empty.

A number of time facts, giving the number of moves that must be found. These are given as a range of consecutive, ascending integers, starting at 1.

== Output Format ==
The input facts plus a number of move facts equal to the number of time facts.  Each move fact is of the form:

move(T,D,X,Y).

indicating that to get to time step T from time step T-1 (the initial conditions are regarded to be time step 0), the peg in position (X,Y) is moved in direction D (up, down, left or right).

== Example ==

== Calibration ==
Generally the fewer pegs remaining on the board, the harder it is to make a move.  Thus instances starting with a full or a nearly full board and conduct 27-31 moves are the most difficult.

== Comment ==
This problem took part in the Second ASP Competition and was proposed by Martin Brain.

== Author(s) ==
 * Yuliya Lierler
  * University of Kentucky, USA
 * Marcello Balduccini
  * Kodak Research Labs, USA