C language Nukikabe pencil-puzzle solver and generator.

What's going on behind the curtains? Here are some details...

The board is represented as a 2D array of cells bellonging to one of the 3 following types:

• WATER for water cells.
• LAND for island cells.
• EMPTY for cells that have not been set yet.

The generator picks a random cell from the board, sets it to WATER and recurses in orthogonal cells, affecting them to LAND or WATER randomly. For each itteration, the posibility of a 2 by 2 WATER pool is checked ensuring that no such pools are created.

Once the algorithm explored all cells or got stuck, empty cells are affected to LAND. If the largest island is larger than the number of rows or columns of the board minus 1, it cell are set to EMPTY before re-calling the generator on an empty cell orthogonaly adjacent to a WATER cell.

The hints are then asigned to a random cell of each island.

• Many thanks to: Generating rationally solvable instances of NP-hard logic puzzles
• To: Counting Islands in Nurikabe
• And: On The NP-Completeness of The Nurikabe Pencil Puzzle and Variants Thereof