Search Results

Search found 5960 results on 239 pages for 'numbers'.

Page 202/239 | < Previous Page | 198 199 200 201 202 203 204 205 206 207 208 209  | Next Page >

• What makes people think that NNs have more computational power than existing models?

  - by Bubba88

  I've read in Wikipedia that neural-network functions defined on a field of arbitrary real/rational numbers (along with algorithmic schemas, and the speculative `transrecursive' models) have more computational power than the computers we use today. Of course it was a page of russian wikipedia (ru.wikipedia.org) and that may be not properly proven, but that's not the only source of such.. rumors Now, the thing that I really do not understand is: How can a string-rewriting machine (NNs are exactly string-rewriting machines just as Turing machines are; only programming language is different) be more powerful than a universally capable U-machine? Yes, the descriptive instrument is really different, but the fact is that any function of such class can be (easily or not) turned to be a legal Turing-machine. Am I wrong? Do I miss something important? What is the cause of people saying that? I do know that the fenomenum of undecidability is widely accepted today (though not consistently proven according to what I've read), but I do not really see a smallest chance of NNs being able to solve that particular problem. Add-in: Not consistently proven according to what I've read - I meant that you might want to take a look at A. Zenkin's (russian mathematician) papers after mid-90-s where he persuasively postulates the wrongness of G. Cantor's concepts, including transfinite sets, uncountable sets, diagonalization method (method used in the proof of undecidability by Turing) and maybe others. Even Goedel's incompletness theorems were proven in right way in only 21-st century.. That's all just to plug Zenkin's work to the post cause I don't know how widespread that knowledge is in CS community so forgive me if that did look stupid. Thank you!

  Read the article

• Determining what action an NPC will take, when it is partially random but influenced by preferences?

  - by lala

  I want to make characters in a game perform actions that are partially random but also influenced by preferences. For instance, if a character feels angry they have a higher chance of yelling than telling a joke. So I'm thinking about how to determine which action the character will take. Here are the ideas that have come to me. Solution #1: Iterate over every possible action. For each action do a random roll, then add the preference value to that random number. The action with the highest value is the one the character takes. Solution #2: Assign a range of numbers to an action, with more likely actions having a wider range. So, if the random roll returns anywhere from 1-5, the character will tell a joke. If it returns 6-75, they will yell. And so on. Solution #3: Group all the actions and make a branching tree. Will they take a friendly action or a hostile action? The random roll (with preference values added) says hostile. Will they make a physical attack or verbal? The random roll says verbal. Keep going down the line until you reach the action. Solution #1 is the simplest, but hardly efficient. I think Solution #3 is a little more complicated, but isn't it more efficient? Does anyone have any more insight into this particular problem? Is #3 the best solution? Is there a better solution?

  Read the article

• Use ini/appconfig file or sql server file to store user config?

  - by h2g2java

  I know that the preference for INI or appconfig XML is their human readability. Let's say user preferences stored for my app are hierarchical and numbers about a thousand items and it would be really confusing for a user to edit an INI to change things anyway. I have always been using a combination of INI with appconfig. I am leaning towards using sql server db file, now. Every time the user changes a preference while using the app, it would be stored into the db file - that's my line of thought. I am also thinking that such a config db file could move around with the app too, just like an INI. Before I do that, any advice 1. If there are any disadvantages against using a db file over INI or appconfig. 2. If a shop uses mysql or oracle, do you think your colleagues would lift up their pro-mysql or pro-oracle eyebrow questioning why you would use sql server technology in a mysql or oracle shop? I mean, I am just using it like an INI file or app.config anyway, right?

  Read the article

• Domain model for an optional many-many relationship

  - by Greg

  Let's say I'm modeling phone numbers. I have one entity for PhoneNumber, and one for Person. There's a link table that expresses the link (if any) between the PhoneNumber and Person. The link table also has a field for DisplayOrder. When accessing my domain model, I have several Use Cases for viewing a Person. I can look at them without any PhoneNumber information. I can look at them for a specific PhoneNumber. I can look at them and all of their current (or past) PhoneNumbers. I'm trying to model Person, not only for the standard CRUD operations, but for the (un)assignment of PhoneNumbers to a Person. I'm having trouble expressing the relationship between the two, especially with respects to the DisplayOrder property. I can think of several solutions but I'm not sure of which (if any) would be best. A PhoneNumberPerson class that has a Person and PhoneNumber property (most closely resembles database design) A PhoneCarryingPerson class that inherits from Person and has a PhoneNumber property. A PhoneNumber and/or PhoneNumbers property on Person (and vis-a-versa, a Person property on PhoneNumber) What would be a good way to model this that makes sense from a domain model perspective? How do I avoid misplaced properties (DisplayOrder on Person) or conditionally populated properties?

  Read the article

• How do I ensure that a regex does not match an empty string?

  - by Dancrumb

  I'm using the Jison parser generator for Javascript and am having problems with my language specification. The program I'm writing will be a calculator that can handle feet, inches and sixteenths. In order to do this, I have the following specification: %% ([0-9]+\s*"'")?\s*([0-9]+\s*"\"")?\s*([0-9]+\s*"s")? {return 'FIS';} [0-9]+("."[0-9]+)?\b {return 'NUMBER';} \s+ {/* skip whitespace */} "*" {return '*';} "/" {return '/';} "-" {return '-';} "+" {return '+';} "(" {return '(';} ")" {return ')';} <<EOF>> {return 'EOF';} Most of these lines come from a basic calculator specification. I simply added the first line. The regex correctly matches feet, inch, sixteenths, such as 6'4" (six feet, 4 inches) or 4"5s (4 inches, 5 sixteenths) with any kind of whitespace between the numbers and indicators. The problem is that the regex also matches a null string. As a result, the lexical analysis always records a FIS at the start of the line and then the parsing fails. Here is my question: is there a way to modify this regex to guarantee that it will only match a non-zero length string?

  Read the article

• resizing images with imagemagick via shell script

  - by jml

  Hi there, I don't really know that much about bash scripts OR imagemagick, but I am attempting to create a script in which you can give some sort of regexp matching pattern for a list of images and then process those into new files that have a given filename prefix. for example given the following dir listing: allfiles01.jpg allfiles02.jpg allfiles03.jpg i would like to call the script like so: ./resisemany.sh allfiles*.jpg 30 newnames*.jpg the end result of this would be that you get a bunch of new files with newnames, the numbers match up, so far what i have is: IMAGELIST=$1 RESIEZFACTOR=$2 NUMIMGS=length($IMAGELIST) for(i=0; i<NUMIMGS; i++) convert $IMAGELIST[i] -filter bessel -resize . RESIZEFACTOR . % myfile.JPG Thanks for any help... The parts that I obviously need help with are 1. how to give a bash script matching criteria that it understands 2. how to use the $2 without having it match the 2nd item in the image list 3. how to get the length of the image list 4. how to create a proper for loop in such a case 5. how to do proper text replacement for a shell command whereby you are appending items as i allude to. jml

  Read the article

• [Ruby] Object assignment and pointers

  - by Jergason

  I am a little confused about object assignment and pointers in Ruby, and coded up this snippet to test my assumptions. class Foo attr_accessor :one, :two def initialize(one, two) @one = one @two = two end end bar = Foo.new(1, 2) beans = bar puts bar puts beans beans.one = 2 puts bar puts beans puts beans.one puts bar.one I had assumed that when I assigned bar to beans, it would create a copy of the object, and modifying one would not affect the other. Alas, the output shows otherwise. ^_^[jergason:~]$ ruby test.rb #<Foo:0x100155c60> #<Foo:0x100155c60> #<Foo:0x100155c60> #<Foo:0x100155c60> 2 2 I believe that the numbers have something to do with the address of the object, and they are the same for both beans and bar, and when I modify beans, bar gets changed as well, which is not what I had expected. It appears that I am only creating a pointer to the object, not a copy of it. What do I need to do to copy the object on assignment, instead of creating a pointer? Tests with the Array class shows some strange behavior as well. foo = [0, 1, 2, 3, 4, 5] baz = foo puts "foo is #{foo}" puts "baz is #{baz}" foo.pop puts "foo is #{foo}" puts "baz is #{baz}" foo += ["a hill of beans is a wonderful thing"] puts "foo is #{foo}" puts "baz is #{baz}" This produces the following wonky output: foo is 012345 baz is 012345 foo is 01234 baz is 01234 foo is 01234a hill of beans is a wonderful thing baz is 01234 This blows my mind. Calling pop on foo affects baz as well, so it isn't a copy, but concatenating something onto foo only affects foo, and not baz. So when am I dealing with the original object, and when am I dealing with a copy? In my own classes, how can I make sure that assignment copies, and doesn't make pointers? Help this confused guy out.

  Read the article

• Easiest way to plot values as symbols in scatter plot?

  - by AllenH

  In an answer to an earlier question of mine regarding fixing the colorspace for scatter images of 4D data, Tom10 suggested plotting values as symbols in order to double-check my data. An excellent idea. I've run some similar demos in the past, but I can't for the life of me find the demo I remember being quite simple. So, what's the easiest way to plot numerical values as the symbol in a scatter plot instead of 'o' for example? Tom10 suggested plt.txt(x,y,value)- and that is the implementation used in a number of examples. I however wonder if there's an easy way to evaluate "value" from my array of numbers? Can one simply say: str(valuearray) ? Do you need a loop to evaluate the values for plotting as suggested in the matplotlib demo section for 3D text scatter plots? Their example produces: However, they're doing something fairly complex in evaluating the locations as well as changing text direction based on data. So, is there a cute way to plot x,y,C data (where C is a value often taken as the color in the plot data- but instead I wish to make the symbol)? Again, I think we have a fair answer to this- I just wonder if there's an easier way?

  Read the article

• How to make placeholder varablies in jquery validate 1.7?

  - by chobo2

  Hi I am using jquery 1.4.2 and jquery validate 1.7(http://bassistance.de/jquery-plugins/jquery-plugin-validation/) Say I have this example that I just grabbed off some random site(http://www.webreference.com/programming/javascript/jquery/form_validation/) 8 <script type="text/javascript"> 9 $(document).ready(function() { 10 $("#form1").validate({ 11 rules: { 12 name: "required",// simple rule, converted to {required:true} 13 email: {// compound rule 14 required: true, 15 email: true 16 }, 17 url: { 18 url: true 19 }, 20 comment: { 21 required: true 22 } 23 }, 24 messages: { 25 comment: "Please enter a comment." 26 } 27 }); 28 }); 29 </script> now is it possible to do something like this 10 $("#form1").validate({ var NameHolder = "name" 11 rules: { 12 NameHolder: "required",// simple rule, converted to {required:true} 13 email: {// compound rule 14 required: true, 15 email: true So basically I want to make sort of a global variable to hold theses rule names( what correspond to the names on that html control). My concern is the names of html controls can change and it kinda sucks that I will have to go around and change it in many places of my code to make it work again. So basically I am wondering is there away to make a global variable to store this name. So if I need to change the name I only have to change it in one spot in my javascript file sort of the way stopping magic numbers ?

  Read the article

• RichFaces a4j:support parameter passing

  - by Mark Lewis

  Hello I have a number of rich:inplaceInput tags in RichFaces which represent numbers in an array. The validator allows integers only. When a user clicks in an input and changes a value, how can I get the bean to sort the array given the new number and reRender the list of rich:inplaceInput tags so that they're in numerical order? EG <a4j:region> <rich:dataTable value="#{MyBacking.config}" var="feed" cellpadding="0" cellspacing="0" width="100%" border="0" columns="5" id="Admin"> ... <a4j:repeat... <a4j:region id="MsgCon"> <rich:inplaceInput value="#{h.id}" validator="#{MyBacking.validateID}" id="andID" showControls="true"> <a4j:support event="onviewactivated" action="#{MyBacking.sort}" reRender="Admin" /> </rich:inplaceInput> </a4j:region> </a4j:repeat> </data:Table> </a4j:region> Note I do NOT want to use dataTable sort functions. The table is complicated and I've specified id="Admin" (ie the whole table) to reRender as I've not found a way to send more localised values to the backing bean through the inplaceInput. This question is about how to use a4j:support action attribute to call the sort method so that when the reRender rerenders the component, it outputs the list in sorted order. I have the sort method working ok when I click a button to sort, but I want to have the list sorted automatically as soon as a new valid value is entered into the inplaceInput component. Thanks

  Read the article

• Creating a Function in SQL Server with a Phone Number as a parameter and returns a Random Number

  - by Emer

  Hi Guys, I am hoping someone can help me here as google is not being as forthcoming as I would have liked. I am relatively new to SQL Server and so this is the first function I have set myself to do. The outline of the function is that it has a Phone number varchar(15) as a parameter, it checks that this number is a proper number, i.e. it is 8 digits long and contains only numbers. The main character I am trying to avoid is '+'. Good Number = 12345678 Bad Number = +12345678. Once the number is checked I would like to produce a random number for each phone number that is passed in. I have looked at substrings, the like operator, Rand(), left(), Right() in order to search through the number and then produce a random number. I understand that Rand() will produce the same random number unless alterations are done to it but right now it is about actually getting some working code. Any hints on this would be great or even point me towards some more documentation. I have read books online and they haven't helped me, maybe I am not looking in the right places. Here is a snippet of code I was working on the Rand declare @Phone Varchar (15) declare @Counter Varchar (1) declare @NewNumber Varchar(15) set @Phone = '12345678' set @Counter = len(@Phone) while @Counter > 0 begin select case when @Phone like '%[0-9]%' then cast(rand()*100000000 as int) else 'Bad Number' end set @counter = @counter - 1 end return Thanks for the help in advance Emer

  Read the article

• Rails: creating a custom data type, to use with generator classes and a bunch of questions related t

  - by Shyam

  Hi, After being productive with Rails for some weeks, I learned some tricks and got some experience with the framework. About 10 days ago, I figured out it is possible to build a custom data type for migrations by adding some code in the Table definition. Also, after learning a bit about floating points (and how evil they are) vs integers, the money gem and other possible solutions, I decided I didn't WANT to use the money gem, but instead try to learn more about programming and finding a solution myself. Some suggestions said that I should be using integers, one for the whole numbers and one for the cents. When playing in script/console, I discovered how easy it is to work with calculations and arrays. But, I am talking to much (and the reason I am, is to give some sufficient background). Right now, while playing with the scaffold generator (yes, I use it, because I like they way I can quickly set up a prototype while I am still researching my objectives), I like to use a DRY method. In my opinion, I should build a custom "object", that can hold two variables (Fixnum), one for the whole, one for the cents. In my big dream, I would be able to do the following: script/generate scaffold Cake name:string description:text cost:mycustom Where mycustom should create two integer columns (one for wholes, one for cents). Right now I could do this by doing: script/generate scaffold Cake name:string description:text cost_w:integer cost_c:integer I had also had an idea that would be creating a "cost model", which would hold two columns of integers and create a cost_id column to my scaffold. But wouldn't that be an extra table that would cause some kind of performance penalty? And wouldn't that be defy the purpose of the Cake model in the first place, because the costs are an attribute of individual Cake entries? The reason why I would want to have such a functionality because I am thinking of having multiple "costs" inside my rails application. Thank you for your feedback, comments and answers! I hope my message got through as understandable, my apologies for incorrect grammar or weird sentences as English is not my native language.

  Read the article

• Project Euler, Problem 10 java solution not working

  - by Dennis S

  Hi, I'm trying to find the sum of the prime numbers < 2'000'000. This is my solution in java but I can't seem get the correct answer. Please give some input on what could be wrong and general advice on the code is appreciated. Printing 'sum' gives: 1308111344, which is incorrect. /* The sum of the primes below 10 is 2 + 3 + 5 + 7 = 17. Find the sum of all the primes below two million. */ class Helper{ public void run(){ Integer sum = 0; for(int i = 2; i < 2000000; i++){ if(isPrime(i)) sum += i; } System.out.println(sum); } private boolean isPrime(int nr){ if(nr == 2) return true; else if(nr == 1) return false; if(nr % 2 == 0) return false; for(int i = 3; i < Math.sqrt(nr); i += 2){ if(nr % i == 0) return false; } return true; } } class Problem{ public static void main(String[] args){ Helper p = new Helper(); p.run(); } }

  Read the article

• floating point equality in Python and in general

  - by eric.frederich

  I have a piece of code that behaves differently depending on whether I go through a dictionary to get conversion factors or whether I use them directly. The following piece of code will print 1.0 == 1.0 -> False But if you replace factors[units_from] with 10.0 and factors[units_to ] with 1.0 / 2.54 it will print 1.0 == 1.0 -> True #!/usr/bin/env python base = 'cm' factors = { 'cm' : 1.0, 'mm' : 10.0, 'm' : 0.01, 'km' : 1.0e-5, 'in' : 1.0 / 2.54, 'ft' : 1.0 / 2.54 / 12.0, 'yd' : 1.0 / 2.54 / 12.0 / 3.0, 'mile' : 1.0 / 2.54 / 12.0 / 5280, 'lightyear' : 1.0 / 2.54 / 12.0 / 5280 / 5.87849981e12, } # convert 25.4 mm to inches val = 25.4 units_from = 'mm' units_to = 'in' base_value = val / factors[units_from] ret = base_value * factors[units_to ] print ret, '==', 1.0, '->', ret == 1.0 Let me first say that I am pretty sure what is going on here. I have seen it before in C, just never in Python but since Python in implemented in C we're seeing it. I know that floating point numbers will change values going from a CPU register to cache and back. I know that comparing what should be two equal variables will return false if one of them was paged out while the other stayed resident in a register. Questions What is the best way to avoid problems like this?... In Python or in general. Am I doing something completely wrong? Side Note This is obviously part of a stripped down example but what I'm trying to do is come with with classes of length, volume, etc that can compare against other objects of the same class but with different units. Rhetorical Questions If this is a potentially dangerous problem since it makes programs behave in an undetermanistic matter, should compilers warn or error when they detect that you're checking equality of floats Should compilers support an option to replace all float equality checks with a 'close enough' function? Do compilers already do this and I just can't find the information.

  Read the article

• Scala newbie vproducer/consumer attempt running out of memory

  - by Nick

  I am trying to create a producer/consumer type Scala app. The LoopControl just sends a message to the MessageReceiver continually. The MessageReceiver then delegates work to the MessageCreatorActor (whose work is to check a map for an object, and if not found create one and start it up). Each MessageActor created by this MessageCreatorActor is associated with an Id. Eventually this is where I want to do business logic. But I run out of memory after 15 minutes. Its finding the cached actors,but quickly runs out of memory. Any help is appreciated. Or any one has any good code on producers consumers doing real stuff (not just adding numbers), please post. import scala.actors.Actor import java.util.HashMap import scala.actors.Actor._ case object LoopControl case object MessageReceiver case object MessageActor case object MessageActorCreator class MessageReceiver(msg: String) extends Actor { var messageActorMap = new HashMap[String, MessageActor] val messageCreatorActor = new MessageActorCreator(null, null) def act() { messageCreatorActor.start loop { react { case MessageActor(messageId) => if (msg.length() > 0) { var messageActor = messageActorMap.get(messageId); if(messageActor == null) { messageCreatorActor ! MessageActorCreator(messageId, messageActorMap) }else { messageActor ! MessageActor } } } } } } case class MessageActorCreator(msg:String, messageActorMap: HashMap[String, MessageActor]) extends Actor { def act() { loop { react { case MessageActorCreator(messageId, messageActorMap) => if(messageId != null ) { var messageActor = new MessageActor(messageId); messageActorMap.put(messageId, messageActor) println(messageActorMap) messageActor.start messageActor ! MessageActor } } } } } class LoopControl(messageReceiver:MessageReceiver) extends Actor { var count : Int = 0; def act() { while (true) { messageReceiver ! MessageActor ("00-122-0X95-FEC0" + count) //Thread.sleep(100) count = count +1; if(count > 5) { count = 0; } } } } case class MessageActor(msg: String) extends Actor { def act() { loop { react { case MessageActor => println() println("MessageActor: Got something-> " + msg) } } } } object messages extends Application { val messageReceiver = new MessageReceiver("bootstrap") val loopControl = new LoopControl(messageReceiver) messageReceiver.start loopControl.start }

  Read the article

• How to efficiently compare the sign of two floating-point values while handling negative zeros

  - by François Beaune

  Given two floating-point numbers, I'm looking for an efficient way to check if they have the same sign, given that if any of the two values is zero (+0.0 or -0.0), they should be considered to have the same sign. For instance, SameSign(1.0, 2.0) should return true SameSign(-1.0, -2.0) should return true SameSign(-1.0, 2.0) should return false SameSign(0.0, 1.0) should return true SameSign(0.0, -1.0) should return true SameSign(-0.0, 1.0) should return true SameSign(-0.0, -1.0) should return true A naive but correct implementation of SameSign in C++ would be: bool SameSign(float a, float b) { if (fabs(a) == 0.0f || fabs(b) == 0.0f) return true; return (a >= 0.0f) == (b >= 0.0f); } Assuming the IEEE floating-point model, here's a variant of SameSign that compiles to branchless code (at least with with Visual C++ 2008): bool SameSign(float a, float b) { int ia = binary_cast<int>(a); int ib = binary_cast<int>(b); int az = (ia & 0x7FFFFFFF) == 0; int bz = (ib & 0x7FFFFFFF) == 0; int ab = (ia ^ ib) >= 0; return (az | bz | ab) != 0; } with binary_cast defined as follow: template <typename Target, typename Source> inline Target binary_cast(Source s) { union { Source m_source; Target m_target; } u; u.m_source = s; return u.m_target; } I'm looking for two things: A faster, more efficient implementation of SameSign, using bit tricks, FPU tricks or even SSE intrinsics. An efficient extension of SameSign to three values.

  Read the article

• GROUP BY ID range?

  - by d0ugal

  Given a data set like this; +-----+---------------------+--------+ | id | date | result | +-----+---------------------+--------+ | 121 | 2009-07-11 13:23:24 | -1 | | 122 | 2009-07-11 13:23:24 | -1 | | 123 | 2009-07-11 13:23:24 | -1 | | 124 | 2009-07-11 13:23:24 | -1 | | 125 | 2009-07-11 13:23:24 | -1 | | 126 | 2009-07-11 13:23:24 | -1 | | 127 | 2009-07-11 13:23:24 | -1 | | 128 | 2009-07-11 13:23:24 | -1 | | 129 | 2009-07-11 13:23:24 | -1 | | 130 | 2009-07-11 13:23:24 | -1 | | 131 | 2009-07-11 13:23:24 | -1 | | 132 | 2009-07-11 13:23:24 | -1 | | 133 | 2009-07-11 13:23:24 | -1 | | 134 | 2009-07-11 13:23:24 | -1 | | 135 | 2009-07-11 13:23:24 | -1 | | 136 | 2009-07-11 13:23:24 | -1 | | 137 | 2009-07-11 13:23:24 | -1 | | 138 | 2009-07-11 13:23:24 | 1 | | 139 | 2009-07-11 13:23:24 | 0 | | 140 | 2009-07-11 13:23:24 | -1 | +-----+---------------------+--------+ How would I go about grouping the results by day 5 records at a time. The above results is part of the live data, there is over 100,000 results rows in the table and its growing. Basically I want to measure the change over time, so want to take a SUM of the result every X records. In the real data I'll be doing it ever 100 or 1000 but for the data above perhaps every 5. If i could sort it by date I would do something like this; SELECT DATE_FORMAT(date, '%h%i') ym, COUNT(result) 'Total Games', SUM(result) as 'Score' FROM nn_log GROUP BY ym; I can't figure out a way of doing something similar with numbers. The order is sorted by the date but I hope to split the data up every x results. It's safe to assume there are no blank rows. Doing it above with the data you could do multiple selects like; SELECT SUM(result) FROM table LIMIT 0,5; SELECT SUM(result) FROM table LIMIT 5,5; SELECT SUM(result) FROM table LIMIT 10,5; Thats obviously not a very good way to scale up to a bigger problem. I could just write a loop but I'd like to reduce the number of queries.

  Read the article

• Array: Recursive problem cracked me up

  - by VaioIsBorn

  An array of integers A[i] (i 1) is defined in the following way: an element A[k] ( k 1) is the smallest number greater than A[k-1] such that the sum of its digits is equal to the sum of the digits of the number 4* A[k-1] . You need to write a program that calculates the N th number in this array based on the given first element A[1] . INPUT: In one line of standard input there are two numbers seperated with a single space: A[1] (1 <= A[1] <= 100) and N (1 <= N <= 10000). OUTPUT: The standard output should only contain a single integer A[N] , the Nth number of the defined sequence. Input: 7 4 Output: 79 Explanation: Elements of the array are as follows: 7, 19, 49, 79... and the 4th element is solution. I tried solving this by coding a separate function that for a given number A[k] calculates the sum of it's digits and finds the smallest number greater than A[k-1] as it says in the problem, but with no success. The first testing failed because of a memory limit, the second testing failed because of a time limit, and now i don't have any possible idea how to solve this. One friend suggested recursion, but i don't know how to set that. Anyone who can help me in any way please write, also suggest some ideas about using recursion/DP for solving this problem. Thanks.

  Read the article

• Simple encryption - Sum of Hashes in C

  - by Dogbert

  I am attempting to demonstrate a simple proof of concept with respect to a vulnerability in a piece of code in a game written in C. Let's say that we want to validate a character login. The login is handled by the user choosing n items, (let's just assume n=5 for now) from a graphical menu. The items are all medieval themed: eg: _______________________________ | | | | | Bow | Sword | Staff | |-----------|-----------|-------| | Shield | Potion | Gold | |___________|___________|_______| The user must click on each item, then choose a number for each item. The validation algorithm then does the following: Determines which items were selected Drops each string to lowercase (ie: Bow becomes bow, etc) Calculates a simple string hash for each string (ie: `bow = b=2, o=15, w=23, sum = (2+15+23=40) Multiplies the hash by the value the user selected for the corresponding item; This new value is called the key Sums together the keys for each of the selected items; this is the final validation hash IMPORTANT: The validator will accept this hash, along with non-zero multiples of it (ie: if the final hash equals 1111, then 2222, 3333, 8888, etc are also valid). So, for example, let's say I select: Bow (1) Sword (2) Staff (10) Shield (1) Potion (6) The algorithm drops each of these strings to lowercase, calculates their string hashes, multiplies that hash by the number selected for each string, then sums these keys together. eg: Final_Validation_Hash = 1*HASH(Bow) + 2*HASH(Sword) + 10*HASH(Staff) + 1*HASH(Shield) + 6*HASH(Potion) By application of Euler's Method, I plan to demonstrate that these hashes are not unique, and want to devise a simple application to prove it. in my case, for 5 items, I would essentially be trying to calculate: (B)(y) = (A_1)(x_1) + (A_2)(x_2) + (A_3)(x_3) + (A_4)(x_4) + (A_5)(x_5) Where: B is arbitrary A_j are the selected coefficients/values for each string/category x_j are the hash values for each string/category y is the final validation hash (eg: 1111 above) B,y,A_j,x_j are all discrete-valued, positive, and non-zero (ie: natural numbers) Can someone either assist me in solving this problem or point me to a similar example (ie: code, worked out equations, etc)? I just need to solve the final step (ie: (B)(Y) = ...). Thank you all in advance.

  Read the article

• Data Structures for Junior Java Developer

  - by user1639637

  Ok,still learning Arrays. I wrote this code which fills the array named "rand" with random numbers between 0 and 1( exclusive). I want to start learning Complexity. the For loop executes n times (100 times) ,every time it takes O(1) time,so the worse case scenario is O(n),am I right? Also,I used ArrayList to store the 100 elements and I imported "Collections" and used Collections.sort() method to sort the elements. import java.util.Arrays; public class random { public static void main(String args[]) { double[] rand=new double[10]; for(int i=0;i<rand.length;i++) { rand[i]=(double) Math.random(); System.out.println(rand[i]); } Arrays.sort(rand); System.out.println(Arrays.toString(rand)); } } ArrayList: import java.util.ArrayList; import java.util.Collections; public class random { public static void main(String args[]) { ArrayList<Double> MyArrayList=new ArrayList<Double>(); for(int i=0;i<100;i++) { MyArrayList.add(Math.random()); } Collections.sort(MyArrayList); for(int j=0;j<MyArrayList.size();j++) { System.out.println(MyArrayList.get(j)); } } }

  Read the article

• What's the recommended implementation for hashing OLE Variants?

  - by Barry Kelly

  OLE Variants, as used by older versions of Visual Basic and pervasively in COM Automation, can store lots of different types: basic types like integers and floats, more complicated types like strings and arrays, and all the way up to IDispatch implementations and pointers in the form of ByRef variants. Variants are also weakly typed: they convert the value to another type without warning depending on which operator you apply and what the current types are of the values passed to the operator. For example, comparing two variants, one containing the integer 1 and another containing the string "1", for equality will return True. So assuming that I'm working with variants at the underlying data level (e.g. VARIANT in C++ or TVarData in Delphi - i.e. the big union of different possible values), how should I hash variants consistently so that they obey the right rules? Rules: Variants that hash unequally should compare as unequal, both in sorting and direct equality Variants that compare as equal for both sorting and direct equality should hash as equal It's OK if I have to use different sorting and direct comparison rules in order to make the hashing fit. The way I'm currently working is I'm normalizing the variants to strings (if they fit), and treating them as strings, otherwise I'm working with the variant data as if it was an opaque blob, and hashing and comparing its raw bytes. That has some limitations, of course: numbers 1..10 sort as [1, 10, 2, ... 9] etc. This is mildly annoying, but it is consistent and it is very little work. However, I do wonder if there is an accepted practice for this problem.

  Read the article

• I did my own web framework: now, how keep it sync with applications? must I use versions?

  - by Daniel Koch

  ... and I did the first web application using it, now I'm going to create the second. In this first web application I enhanced the framework's core library with new things and promptly updated framework branch. I'm using bazaar to keep framework and web application committed. The application was in the beginning, a full branch of framework source tree, now I'm updating framework manually at every change on core files. (copying changed files from web app to framework's branch). With this second web application that I'm going to create, I need to know about versions (or revisions) which the application is based. If I found a bug in this version I can fix and then sync files with first web application no worrying: functions will be the same to this application. If I'm going to make changes in core (new behavior, new functions in library or something new in source tree) it must be named as "new version". What's the best way to do this? Because I'm using a Distributed Version Control System (bazaar), I'm not dealing with VERSIONS, but revision numbers that change every time. Please fresh my mind with new ideas.

  Read the article

• how to fix my error saying expected expression before 'else'

  - by user292489

  this program intended to read a .txt, a set of numbers, file and wwrite to another two .txt files called even amd odd as follows: #include <stdio.h> #include <stdlib.h> int main(int argc, char *argv[]) { int i=0,even,odd; int number[i]; // check to make sure that all the file names are entered if (argc != 3) { printf("Usage: executable in_file output_file\n"); exit(0); } FILE *dog = fopen(argv[1], "r"); FILE *feven= fopen(argv[2], "w"); FILE *fodd= fopen (argv[3], "w"); // check whether the file has been opened successfully if (dog == NULL) { printf("File %s cannot open!\n", argv[1]); exit(0); } //odd = fopen(argv[2], "w"); { if (i%2!=1) i++;} fprintf(feven, "%d", even); fscanf(dog, "%d", &number[i]); else { i%2==1; i++;} fprintf(fodd, "%d", odd); fscanf(dog, "%d", &number[i]); fclose(feven); fclose(fodd);

  Read the article

• How to properly translate the "var" result of a lambda expression to a concrete type?

  - by CrimsonX

  So I'm trying to learn more about lambda expressions. I read this question on stackoverflow, concurred with the chosen answer, and have attempted to implement the algorithm using a console app in C# using a simple LINQ expression. My question is: how do I translate the "var result" of the lambda expression into a usable object that I can then print the result? I would also appreciate an in-depth explanation of what is happening when I declare the outer => outer.Value.Frequency (I've read numerous explanations of lambda expressions but additional clarification would help) C# //Input : {5, 13, 6, 5, 13, 7, 8, 6, 5} //Output : {5, 5, 5, 13, 13, 6, 6, 7, 8} //The question is to arrange the numbers in the array in decreasing order of their frequency, preserving the order of their occurrence. //If there is a tie, like in this example between 13 and 6, then the number occurring first in the input array would come first in the output array. List<int> input = new List<int>(); input.Add(5); input.Add(13); input.Add(6); input.Add(5); input.Add(13); input.Add(7); input.Add(8); input.Add(6); input.Add(5); Dictionary<int, FrequencyAndValue> dictionary = new Dictionary<int, FrequencyAndValue>(); foreach (int number in input) { if (!dictionary.ContainsKey(number)) { dictionary.Add(number, new FrequencyAndValue(1, number) ); } else { dictionary[number].Frequency++; } } var result = dictionary.OrderByDescending(outer => outer.Value.Frequency); // How to translate the result into something I can print??

  Read the article

• How to deserialize implementation classes in OSGi

  - by Daniel Schneller

  In an eRCP OSGi based application the user can push a button and go to a lock screen similar to that of Windows or Mac OS X. When this happens, the current state of the application is serialized to a file and control is handed over to the lock screen. In this mobile application memory is very tight, so we need to get rid of the original view/controller when the lock screen comes up. This works fine and we end up with a binary serialized file. Once the user logs back in, the file is read in again and the original state of the application restored. This works fine as well, except when the controller that was serialized contained a reference to an object which comes from a different bundle. In my concrete case the original controller (from bundle A) can call a web service and gets a result back. Nothing fancy, just some Strings and Numbers in a simple value holder class. However the controller only sees this as a Result interface; the actual runtime object (ResultImpl) is defined and created in a different bundle (bundle B, the webservice client implementation) and returned via a service call. When the deserialization now tries to thaw the controller from the file, it throws a ClassNotFound exception, complaining about not being able to deserialize the result object, because deserialization is called from bundle A, which cannot see the ResultImpl class from bundle B. Any ideas on how to work around that? The only thing I could come up with is to clone all the individual values into another object, defined in the controller's bundle, but this seems like quite a hassle.

  Read the article

< Previous Page | 198 199 200 201 202 203 204 205 206 207 208 209  | Next Page >