Java-Najdaljše skupno podzaporedje

static String NSZ(String X, String Y)
	{
		if(X == null || Y == null || X.length() == 0 || Y.length() == 0)
			return "";

		if(Character.toString(X.charAt(X.length()-1)).equals(Character.toString(Y.charAt(Y.length()-1))))
		{
			return NSZ(X.substring(0, X.length()-1), Y.substring(0, Y.length()-1)) +String.valueOf(X.charAt(X.length()-1));
		}

		String first = NSZ(X,  Y.substring(0, Y.length()-1)),
		second = NSZ(X.substring(0, X.length()-1), Y);

		if (first.length() >= second.length())
			return first;
		else
			return second;
	}