Generate the list of cells for each row, col, and block at grid creation time, not lazily. This allows us to get rid of the locks--although the speedup doesn't appear to be particularly big.
Generate the list of cells for each row, col, and block at grid creation time, not lazily. This allows us to get rid of the locks--although the speedup doesn't appear to be particularly big.

jkomoros/sudoku,jkomoros/sudoku,jkomoros/sudoku