public Table(int rows, int columns) {
		this.rows = rows;
		this.columns = columns;
		letters = new char[rows*columns];
		typedletters = new int[rows*columns];
		//ׂĂ̒gPɂĂ
		for ( int row=0; row<rows; ++row ) {
			for ( int col=0; col<columns; ++col ) {
				letters[row*columns + col] = '1';
				typedletters[row*columns + col] = 0;
			}
		}
		wordList = new ArrayList<Word>();
		obtainedList = new ArrayList<Word>();
	}