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
This document outlines what is necessary to install and run the LEACH protocol on version 2.27 of ns2. At the time of this writing, this is the newest version of ns2. The LEACH implementation was written as a stand-alone application. Thus, in the past a version compiled for LEACH may or may not work for other protocols. In addition, the original version of LEACH was compiled for version 2.5b which is an outdated version of ns2.
標簽: necessary document outlines protocol
上傳時間: 2014-01-10
上傳用戶:tianjinfan
Lua is a powerful, light-weight programming language designed for extending applications. It is also frequently used as a general-purpose, stand-alone language. It combines simple procedural syntax (similar to Pascal) with powerful data description constructs based on associative arrays and extensible semantics. Lua is dynamically typed, interpreted from bytecodes, and has automatic memory management with garbage collection, making it ideal for configuration, scripting, and rapid prototyping.
標簽: applications light-weight programming extending
上傳時間: 2016-01-13
上傳用戶:1101055045
We have a group of N items (represented by integers from 1 to N), and we know that there is some total order defined for these items. You may assume that no two elements will be equal (for all a, b: a<b or b<a). However, it is expensive to compare two items. Your task is to make a number of comparisons, and then output the sorted order. The cost of determining if a < b is given by the bth integer of element a of costs (space delimited), which is the same as the ath integer of element b. Naturally, you will be judged on the total cost of the comparisons you make before outputting the sorted order. If your order is incorrect, you will receive a 0. Otherwise, your score will be opt/cost, where opt is the best cost anyone has achieved and cost is the total cost of the comparisons you make (so your score for a test case will be between 0 and 1). Your score for the problem will simply be the sum of your scores for the individual test cases.
標簽: represented integers group items
上傳時間: 2016-01-17
上傳用戶:jeffery
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
AutoBoot is a generic boot loader that automatically locates, loads, and executes object files from multiple types of media. AutoBoot provides a simple, fast, and functional means of loading an OS image while maintaining a small Flash memory footprint. This binary release contains a stand-alone version of AutoBoot for the DbAu1200 development board, designed to replace the YAMON boot loader.
標簽: automatically AutoBoot executes generic
上傳時間: 2014-01-14
上傳用戶:海陸空653
Foundations of Python Network Programming leads readers through every aspect of client and server programming with Python. Python is a new and innovative scripting language. It is set to replace Perl as the programming language of choice for scripters and for serious application developers wanting a feature rich yet simple language to deploy their products in. This book features extensive examples that not only demonstrate important concepts and practices, but also provide a cadre of fully-functional stand-alone programs. Readers can use the examples as the basis and building blocks for their own software
標簽: Foundations Programming Network readers
上傳時間: 2013-12-16
上傳用戶:小碼農lz
Is a Application Demo (an example) of how to use the package LCD in order to make an application stand alone that show a scrolling message on display.
標簽: Application application example package
上傳時間: 2016-05-29
上傳用戶:tianyi223
歡迎使用藍牙聯網坦克大戰,運行平臺為Symbian OS 使用說明: 1.打開應用程序,進入手機游戲之后,有三種模式可供您選擇。 Stand Alone模式為單機模式,Server為服務器模式,如果要想用 藍牙進行連接,請先選擇此模式,然后等待開啟客戶端模式。 Client模式為客戶端模式,進入此模式之后,選擇所要的服務器, 然后等待服務器 開啟游戲。 2.在藍牙連接下,連接建立好之后,由服務器進入游戲狀態, 玩家即可開始游戲。 3.方向鍵控制著坦克運行方向,回車鍵控制炮彈發射。當己方 司令部被攻克時,游戲結束。 4.游戲結束時,按“restart”可重新開始;在服務器端點“exit“,則兩端游戲均退出 游戲勝負判定: 勝利:當玩家消滅敵方坦克數量為10時,玩家贏 失敗:如果玩家被敵人干掉,或者司令部被玩家攻破,則游戲失敗
上傳時間: 2013-12-19
上傳用戶:凌云御清風