/**
* Find digits that still can be used in a given empty cell.
* @param emptyCell Empty cell to search still free digits for.
*/
private void findDigitsStillFree(EmptyCell emptyCell) {
emptyCell.setAllDigitsStillFree();
for (int j = 0; j < BOARD_SIZE; j++) {
int boardDigit = sudokuBoard[emptyCell.rowIndex, j];
if (boardDigit != CELL_EMPTY)
emptyCell.digitsStillFree[boardDigit] = DIGIT_IN_USE;
}
for (int i = 0; i < BOARD_SIZE; i++) {
int boardDigit = sudokuBoard[i, emptyCell.colIndex];
if (boardDigit != CELL_EMPTY)
emptyCell.digitsStillFree[boardDigit] = DIGIT_IN_USE;
}
SubSquare sub = SubSquare.getSubSqare(emptyCell);
/*
* Mark digits used in a sub-square.
*/
for (int i = sub.rowMin; i < sub.rowMax; i++)
for (int j = sub.colMin; j < sub.colMax; j++) {
int boardDigit = sudokuBoard[i, j];
if (boardDigit != CELL_EMPTY)
emptyCell.digitsStillFree[boardDigit] = DIGIT_IN_USE;
}
/*
* Find number of still free digits to use.
*/
emptyCell.digitsStillFreeNumber = 0;
for (int digit = 1; digit < 10; digit++)
if (emptyCell.digitsStillFree[digit] == DIGIT_STILL_FREE)
emptyCell.digitsStillFreeNumber++;
}
