private SudokuGrid iteratePartialSolution(int row, int column, SudokuGrid sudokuGrid) {
if (row >= 9) {
return sudokuGrid;
}
iterationCounter++;
int newColumn = (column + 1) % 9;
int newRow = row + (newColumn == 0 ? 1 : 0);
if (sudokuGrid.getFieldValue(row, column) == 0) {
for (byte value = 1; value <= 9; value++) {
// printDebugInfo(row, column, value);
SudokuGrid newSudokuGrid = sudokuGrid.setFieldValue(row, column, value);
if (validateSudokuForField(row, column, newSudokuGrid)) {
SudokuGrid resultSudokuGrid = iteratePartialSolution(newRow, newColumn, newSudokuGrid);
if (resultSudokuGrid != null) {
return resultSudokuGrid;
}
}
sudokuGrid.resetFieldValue(row, column);
}
} else {
return iteratePartialSolution(newRow, newColumn, sudokuGrid);
}
return null;
}
