private final void buildSymboltable(String code, Node<K> node) {
		if (node.getSymbol()!=null) {
			if (code.equals("")) {
				code += "0";
			}
			this.symbols.put(node.getSymbol(), code);
		}
		else {
			if (node.getLeft()!=null) {
				buildSymboltable(code + "0", node.getLeft());
			}
			if (node.getRight()!=null) {
				buildSymboltable(code + "1", node.getRight());
			}
		}
	}