上下文無關(guān)文法（Context-Free Grammar, CFG）是一個(gè)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(chǎn)生式規(guī)則集，形如A→α，其中A∈V，且α∈(V∪T)*。V的元素稱為非終結(jié)符，T的元素稱為終結(jié)符，S是一個(gè)特殊的非終結(jié)符，稱為文法開始符。 設(shè)G=(V, T, S, P)是一個(gè)CFG，則G產(chǎn)生的語言是所有可由G產(chǎn)生的字符串組成的集合，即L(G)={x∈T* | Sx}。一個(gè)語言L是上下文無關(guān)語言（Context-Free Language, CFL），當(dāng)且僅當(dāng)存在一個(gè)CFG G，使得L=L(G)。 *⇒ 例如，設(shè)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(jié)符都是大寫字母，開始符都是S，終結(jié)符都是小寫字母。
標(biāo)簽： Context-Free Grammar CFG
上傳時(shí)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?yàn)樗恼Z言是由以下兩種形式的規(guī)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(gè)魔王語言的解釋系統(tǒng),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(guī)則和上述規(guī)則形式(2)實(shí)現(xiàn).設(shè)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(shù)據(jù): 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(yīng)關(guān)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(shí)間： 2014-12-02
上傳用戶：jkhjkh1982
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(biāo)簽： represented integers group items
上傳時(shí)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(biāo)簽： converts Toolbox complex logical
上傳時(shí)間： 2016-02-12
上傳用戶：a673761058
溫度控制器 顯示為三個(gè)共陽極LED 溫度傳感器用單總線DS18B20 CPU為89C51，三個(gè)按鍵，分別為UP，DOWN，SET 2個(gè)檢測, 溫度調(diào)節(jié)上限為125度，下限為-55度
上傳時(shí)間： 2016-03-25
上傳用戶：LouieWu
Host Identity Protocol on Linux is an implemetation of the Host Identity Protocol (HIP) and the related architecture. HIP is a proposal to change the TCP/IP stack to securely support mobility and multi-homing. Additionally, it provides for enhanced security and privacy and advanced network concepts, such as moving networks and mobile ad hoc networks. HIP is "cool", which means that as a mobile VPN solution, when your network interfaces go up or down, there is no need to re-establish a secure tunnel.
標(biāo)簽： Identity Protocol Host implemetation
上傳時(shí)間： 2016-09-01
上傳用戶：皇族傳媒
溫度控制器V1.5 顯示為三個(gè)共陽極LED 溫度傳感器用單總線DS18B20 CPU為2051，四個(gè)按鍵，分別為UP，DOWN，SET 溫度調(diào)節(jié)上限為125度，下限為-55度 只能用于單只18B20
上傳時(shí)間： 2016-11-28
上傳用戶：2404
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(biāo)簽： the animation Simulate movement
上傳時(shí)間： 2017-02-11
上傳用戶：waizhang
溫度傳感器用單總線DS18B20，CPU為2051，三個(gè)按鍵，分別為UP，DOWN，SET溫度調(diào)節(jié)上限為125度，下限為-55度。
上傳時(shí)間： 2013-12-03
上傳用戶：wlcaption
將魔王的語言抽象為人類的語言：魔王語言由以下兩種規(guī)則由人的語言逐步抽象上去的：α-〉β1β2β3…βm ；θδ1δ2…-〉θδnθδn-1…θδ1 設(shè)大寫字母表示魔王的語言，小寫字母表示人的語言B-〉tAdA，A-〉sae，eg：B(ehnxgz)B解釋為tsaedsaeezegexenehetsaedsae對應(yīng)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-天d-地s-上a-一只e-鵝z-追g-趕x-下n-蛋h-恨)
上傳時(shí)間： 2013-12-19
上傳用戶：aix008
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