/**
	 * To check if HT is empty or not.
	 * 
	 * @return true, if both subtrees are null
	 */
	public boolean isEmpty() {
		return left == null && right == null;
	}

	/**
	 * To check if HT is a leaf.
	 * 
	 * @return true, if actual HT is non-empty, but both subtrees are
	 */
	public boolean isLeaf() {
		return !isEmpty() && left.isEmpty() && right.isEmpty();
	}

	public BitString[] encode(BitString[] codeTable, BitString path) {
		if (isLeaf()) {
			codeTable[name] = path;
			return null;
		}
		right.encode(codeTable, path.append(true));
		left.encode(codeTable, path.append(false));
		return codeTable;
	}