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上下文無關文法（Context-Free Grammar, CFG）是一個4元組G=(V, T, S, P)，其中，V和T是不相交的有限集，S∈V，P是一組有限的產生式規則集，形如A→α，其中A∈V，且α∈(V∪T)*。V的元素稱為非終結符，T的元素稱為終結符，S是一個特殊的非終結符，稱為文法開始符。 設G=(V, T, S, P)是一個CFG，則G產生的語言是所有可由G產生的字符串組成的集合，即L(G)={x∈T* | Sx}。一個語言L是上下文無關語言（Context-Free Language, CFL），當且僅當存在一個CFG G，使得L=L(G)。 *⇒ 例如，設文法G：S→AB A→aA|a B→bB|b 則L(G)={a^nb^m | n,m>=1} 其中非終結符都是大寫字母，開始符都是S，終結符都是小寫字母。
標簽： Context-Free Grammar CFG
上傳時間： 2013-12-10
上傳用戶：gaojiao1999
一:需求分析 1. 問題描述 魔王總是使用自己的一種非常精練而抽象的語言講話,沒人能聽懂,但他的語言是可逐步解釋成人能聽懂的語言,因為他的語言是由以下兩種形式的規則由人的語言逐步抽象上去的: ----------------------------------------------------------- (1) a---> (B1)(B2)....(Bm) (2)[(op1)(p2)...(pn)]---->[o(pn)][o(p(n-1))].....[o(p1)o] ----------------------------------------------------------- 在這兩種形式中,從左到右均表示解釋.試寫一個魔王語言的解釋系統,把 他的話解釋成人能聽得懂的話. 2. 基本要求: 用下述兩條具體規則和上述規則形式(2)實現.設大寫字母表示魔王語言的詞匯 小寫字母表示人的語言的詞匯 希臘字母表示可以用大寫字母或小寫字母代換的變量.魔王語言可含人的詞匯. (1) B --> tAdA (2) A --> sae 3. 測試數據: B(ehnxgz)B 解釋成 tsaedsaeezegexenehetsaedsae若將小寫字母與漢字建立下表所示的對應關系,則魔王說的話是:"天上一只鵝地上一只鵝鵝追鵝趕鵝下鵝蛋鵝恨鵝天上一只鵝地上一只鵝". | t | d | s | a | e | z | g | x | n | h | | 天 | 地 | 上 | 一只| 鵝 | 追 | 趕 | 下 | 蛋 | 恨 |
上傳時間： 2014-12-02
上傳用戶：jkhjkh1982
The Bad Beginning: A Terrible Tale Do you enjoy happy endings? If so, The Bad Beginning by Lemony Snicket is a book you’ll want to avoid. This is a story with a bad beginning, a bad middle and a bad ending. Why would anyone want to read such a thoroughly bad book? It’s all in good fun!
標簽： Beginning The Bad Terrible
上傳時間： 2013-12-28
上傳用戶：笨小孩
This the second tutorial of the Writing Device Drivers series. There seems to be a lot of interest in the topic, so this article will pick up where the first left off. The main focus of these articles will be to build up little by little the knowledge needed to write device drivers. In this article, we will be building on the same example source code used in part one. In this article, we will expand on that code to include Read functionality, Handle Input/Ouput Controls also known as IOCTLs, and learn a bit more about IRPs.
標簽： the interest tutorial Drivers
上傳時間： 2016-01-28
上傳用戶：lmeeworm
The XML Toolbox converts MATLAB data types (such as double, char, struct, complex, sparse, logical) of any level of nesting to XML format and vice versa. For example, >> project.name = MyProject >> project.id = 1234 >> project.param.a = 3.1415 >> project.param.b = 42 becomes with str=xml_format(project, off ) "<project> <name>MyProject</name> <id>1234</id> <param> <a>3.1415</a> <b>42</b> </param> </project>" On the other hand, if an XML string XStr is given, this can be converted easily to a MATLAB data type or structure V with the command V=xml_parse(XStr).
標簽： converts Toolbox complex logical
上傳時間： 2016-02-12
上傳用戶：a673761058
GNU ccScript is a C++ class framework for creating a virtual machine execution system for use with and as a scripting/assembler language for state-transition driven realtime systems. The most common example of this is as the core of the scripting engine found in GNU Bayonne.
標簽： framework for execution ccScript
上傳時間： 2013-12-18
上傳用戶：sssl
OBPM是一個開源，輕量級的BPM系統。它的目標是讓非IT人員也可以輕松構建IT業務處理流程。OBPM內建工作流引擎（Workflow Engine）, Form構建器，Report設計器。
上傳時間： 2016-08-08
上傳用戶：evil
漢諾塔?。。? Simulate the movement of the Towers of Hanoi puzzle Bonus is possible for using animation eg. if n = 2 A→B A→C B→C if n = 3 A→C A→B C→B A→C B→A B→C A→C
標簽： the animation Simulate movement
上傳時間： 2017-02-11
上傳用戶：waizhang
Genetic Algorithm example using Java You have 10 cards numbered 1 to 10. You have to divide them into 2 piles so that: The sum of the first pile is as close as possible to 36 and the product of all in second pile is as close as poss to 360.
標簽： have Algorithm You numbered
上傳時間： 2017-03-08
上傳用戶：lacsx
function to compute an expression using int value parameters throw an exception of type illegalParameterValue in case one of the parameters is <= 0
標簽： illegalPara expression parameters exception
上傳時間： 2014-01-20
上傳用戶：a6697238
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