CSE 5326  HW7

Due: Wednesday, November 20 at midnight (electronically)

Write a Prolog predicate apply_ops(State,NewStates) that functions
similarly to the APPLY-OPS function from HW2.  You should be able to
follow the solution in /usr/student/cs5326/puzzle.lisp when
constructing your Prolog solution.  That is, you can write auxiliary
predicates apply_op(up,Desc,NewDesc), apply_op(down,Desc,NewDesc),
etc., and swap_tiles(Tile1,Tile2,Desc,NewDesc).  Of course, you may
write apply_ops in another way if you choose.

For the Prolog version, a state is a list like:

  [[1,2,3,4,5,6,7,8,0],[up,left,down]]

where the first element of the list is a description of the board,
and the second element of the list if the reverse of the path leading
to the state.  Therefore, the example calls from HW2 will look like:

?- apply_ops([[1,2,3,4,0,5,7,8,6],[]],NewStates).

NewStates = [[[1,0,3,4,2,5,7,8,6],[up]],
             [[1,2,3,4,8,5,7,0,6],[down]],
             [[1,2,3,0,4,5,7,8,6],[left]],
             [[1,2,3,4,5,0,7,8,6],[right]]] ;

no

?- apply_ops([[1,2,3,4,5,0,7,8,6],[right]],NewStates).

NewStates = [[[1,2,0,4,5,3,7,8,6],[up,right]],
             [[1,2,3,4,5,6,7,8,0],[down,right]],
             [[1,2,3,4,0,5,7,8,6],[left,right]]] ;

no

?-

After completing your solution, hand it in using the handin-hw7
program.  Besure to comment your code and test it thoroughly.