public SudokuBoard obfuscate(SudokuBoard board, float percentage) {
if (percentage < 0f || percentage > 1f) {
Log.output(
"ERROR: Cannot obfuscate board. Percentage value is invalid (0 <= percentage <= 1): "
+ percentage);
return null;
}
if (!board.isFilled()) {
Log.output("ERROR: Cannot obfuscate board. Board contains a zero-value.");
return null;
}
int size = board.getBoardSize();
int removalCount = (int) (Math.pow(board.getBoardSize(), 2) * percentage);
SudokuBoard puzzle = new SudokuBoard(board);
int row;
int column;
int value;
while (removalCount > 0) {
row = r.nextInt(size);
column = r.nextInt(size);
value = puzzle.getCell(row, column);
// TODO: Keep track of values that have already been cleared and prevent them from being
// selected again.
if (value != 0) {
puzzle.setCell(row, column, 0);
removalCount--;
}
}
return puzzle;
}