diff options
Diffstat (limited to 'src/sudoku.cc')
| -rw-r--r-- | src/sudoku.cc | 39 |
1 files changed, 29 insertions, 10 deletions
diff --git a/src/sudoku.cc b/src/sudoku.cc index 6c241d9..d55a43b 100644 --- a/src/sudoku.cc +++ b/src/sudoku.cc @@ -39,17 +39,18 @@ void Sudoku::set_value(int row, int column, int cell_value) sudoku_cell[row][column].set_value(cell_value); } -void Sudoku::validate() +// reset the solution space and calculate possible values for all cells +void Sudoku::reset() { for (int row = 0; row < 9; row++) { for (int column = 0; column < 9; column++) { - validate_cell(row, column); + reset_cell(row, column); } } } -// validate_cell calculates the possible values for a cell -void Sudoku::validate_cell(int pos_row, int pos_column) +// reset the solution space for this cell and calculate possible values +void Sudoku::reset_cell(int pos_row, int pos_column) { // reset all possibilities for this cell for (int possible_value = 0; possible_value < 9; possible_value++) { @@ -102,7 +103,7 @@ void Sudoku::validate_cell(int pos_row, int pos_column) int Sudoku::solve_coverage() { // calculate cell.possibilities - validate(); + reset(); Sudoku solution(*this); @@ -151,12 +152,30 @@ int Sudoku::solve_coverage() // verify coverage for each subgrid for (int subgrid = 0; subgrid < 9; subgrid++) { + // global coordinates of the (0,0) element of the subgrid + const int sg_row = (subgrid / 3) * 3; + const int sg_column = (subgrid % 3) * 3; - // TODO the subgrid and subgrididx indices need te be delinearized - // and translated into cell coordinates - - // verify if there's exactly one possibility for v in this subgrid - for (int subgrididx = 0; subgrididx < 9; subgrididx++) { + // transle linear subgrid positions to row, col coordinate + for (int subgrid_pos = 0; subgrid_pos < 9; subgrid_pos++) { + int sg_rowidx = sg_row + subgrid_pos / 3; + int sg_colidx = sg_column + subgrid_pos % 3; + int available_pos = 0; + int covered = 0; + + if (!value(sg_rowidx, sg_colidx) && sudoku_cell[sg_rowidx][sg_colidx].possibility(v - 1)) { + // value is still possible a single cell + available_pos = subgrid_pos; + } else { + covered++; + } + + if (covered == 8) { + // value is only possible for a single cell + int sg_rowidx = sg_row + available_pos / 3; + int sg_colidx = sg_column + available_pos % 3; + solution.set_value(sg_rowidx, sg_colidx, v); + } } } } |