public Sudoku generate() {
		passes = 0;
		Sudoku sudoku = new Sudoku();
		int count = 0;
		while (count < nFill) {
			int row = random.nextInt(9);
			int column = random.nextInt(9);
			
			if (sudoku.fit(row*9 + column, random.nextInt(9)))
				count++;
			passes++;
		}
		//Util.dprint("nFill: " + nFill + ", count: " + count + ", filled: " + (81 - Util.countEmptySlots(sudoku)));
		return sudoku;
	}