Solution
= Solution
The empty occupancy <sets> leave all nine coordinates available:
``
empty :: Board
empty = ([],[],[(r,c) | r <- [0..2], c <- [0..2]])
``
This board satisfies the <representation invariant> and gives `O` the next move.
= Solution
The empty occupancy <sets> leave all nine coordinates available:
``
empty :: Board
empty = ([],[],[(r,c) | r <- [0..2], c <- [0..2]])
``
This board satisfies the <representation invariant> and gives `O` the next move.