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  • How do you protect a common resource using mutexes?

    - by Steve
    I have a common resource, which I want 1 and only 1 instance of my application (or it's COM API) to have access to at any time. I have tried to protect this resource using mutexes, but when multiple threads of a host dotnet application try to access the COM object, the mutex doesn't seem to be released. This is the code I have used to protect my resource. repeat Mutex := CreateMutex(nil, True, PChar('Connections')); until (Mutex <> 0) and (GetLastError <> ERROR_ALREADY_EXISTS); try //use resource here! finally CloseHandle(Mutex); end; If I run the threads simultaneously, the first thread get's through (obviously, being the first one to create the mutex), but subsequent threads are caught in the repeat loop. If I run each thread at 5 second intervals, then all is ok. I suspect I'm not using mutexes correctly here, but I have found very little documentation about how to do this. Any ideas?

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  • multithreading issue

    - by vbNewbie
    I have written a multithreaded crawler and the process is simply creating threads and having them access a list of urls to crawl. They then access the urls and parse the html content. All this seems to work fine. Now when I need to write to tables in a database is when I experience issues. I have 2 declared arraylists that will contain the content each thread parse. The first arraylist is simply the rss feed links and the other arraylist contains the different posts. I then use a for each loop to iterate one while sequentially incrementing the other and writing to the database. My problem is that each time a new thread accesses one of the lists the content is changed and this affects the iteration. I tried using nested loops but it did not work before and this works fine using a single thread.I hope this makes sense. Here is my code: SyncLock dlock For Each l As String In links finallinks.Add(l) Next End SyncLock SyncLock dlock For Each p As String In posts finalposts.Add(p) Next End SyncLock ... Dim i As Integer = 0 SyncLock dlock For Each rsslink As String In finallinks postlink = finalposts.Item(i) i = i + 1 finallinks and finalposts are the two arraylists. I did not include the rest of the code which shows the threads working but this is the essential part where my error occurs which is basically here postlink = finalposts.Item(i) i = i + 1 ERROR: index was out of range. Must be non-negative and less than the size of the collection Is there an alternative?

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  • Java - SwingWorker - problem

    - by Yatendra Goel
    I am developing a Java Desktop Application. This app executes the same task public class MyTask implements Callable<MyObject> { in multiple thread simultaneously. Now, when a user clicks on a "start" button, I have created a SwingWorker myWorker and have executed it. Now, this myWorker creates multiple instances of MyTask and submits them to an ExecutorService. Each MyTask instance has a loop and generates an intermediate result at every iteration. Now, I want to collect these intermediate results from each MyTask instances as soon as they are generated. Then after collecting these intermediate results from every MyTask instance, I want to publish it through SwingWorker.publish(MyObject) so that the progress is shown on the EDT. Q1. How can I implement this? Should I make MyTask subclass of SwingWorker instead of Callable to get intermediate results also, because I think that Callable only returns final result. Q2. If the answer of Q1. is yes, then can you give me a small example to show how can I get those intermediate results and aggregate them and then publish them from main SwingWorker? Q3. If I can't use SwingWorker in this situation, then how can I implement this?

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  • leaflet/JSONobject. Marker onclick show only last record

    - by user2780898
    that my code <div id='map'></div> <div id="info"></div> [...] var markers1 = new L.MarkerClusterGroup( { showCoverageOnHover: true } ); $.ajax({ type: "GET", url: "db.php", success: function (result) { var JSONobject = JSON.parse(result); var jnCount = JSONobject.length; for (var i = 0; i < jnCount; i++) { var marker = new L.Marker(new L.LatLng(JSONobject[i]["lat"],JSONobject[i]["lng"]),{ icon: myIcon1 }); var id = JSONobject[i]["id"]; var list = "<dl>" + "<dt><b>CITTA':</b> " + JSONobject[i]["citta_"] + "</dt>"; marker.on('click', function() { {document.getElementById('info').innerHTML = list;} }); markers1.addLayer(marker); } map.addLayer(markers1); } }); Marker onclick shows only the last record! I think problem is in loop but I don't understand how fix it. Any idea? Thanks Nicola

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  • What is the Proper approach for Constructing a PhysicalAddress object from Byte Array

    - by Paul Farry
    I'm trying to understand what the correct approach for a constructor that accepts a Byte Array with regard to how it stores it's data (specifically with PhysicalAddress) I have an array of 6 bytes (theAddress) that is constructed once. I have a source array of 18bytes (theAddresses) that is loaded from a TCP Connection. I then copy the 6bytes from theAddress+offset into theAddress and construct the PhysicalAddress from it. Problem is that the PhysicalAddress just stores the Reference to the array that was passed in. Therefore if you subsequently check the addresses they only ever point to the last address that was copied in. When I took a look inside the PhysicalAddress with reflector it's easy to see what's going on. public PhysicalAddress(byte[] address) { this.changed = true; this.address = address; } Now I know this can be solved by creating theAddress array on each pass, but I wanted to find out what really is the best practice for this. Should the constructor of an object that accepts a byte array create it's own private Variable for holding the data and copy it from the original Should it just hold the reference to what was passed in. Should I just created theAddress on each pass in the loop

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  • Complex LINQ paging algorithm

    - by sharepointmonkey
    We have a list of projects that may or may not have a collection of subprojects. Our report needs to contain all the projects except those that are the parent project of a subproject. I need to page this into pages of, say, 25 rows. But if subprojects appear on that page then ALL the subprojects of that project must appear on the same page. So more than 25 items may appear if necessary. I've got as far as var pagedProjects = db.Projects.Where(x => !x.SubProjects.Any()).Skip( (pageNo -1) * pageSize).Take(pageSize); Obviously, this fails the second part of the requirements. As a further pain in the arse, I need to have a pager control on the report. So I'll need to be able to calculate the total number of pages. I could loop through the whole table of projects but the performance will suffer. Can anybody come up with a paged solution? EDIT - I should probably mention that SubProjects joins back onto Projects via a selfreferencing foreign key so the whole lot comes back as an IQueryable<Project>.

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  • XSLT inserting once off custom text

    - by BeraCim
    Hi all: The folloiwng is a pre-existing xml file. I was wondering how can I insert a element before the first element using xslt? <XmlFile> <!-- insert another <tag> element here --> <tag> <innerTag> </innerTag> </tag> <tag> <innerTag> </innerTag> </tag> <tag> <innerTag> </innerTag> </tag> </XmlFile> I was thinking of using a for-each loop and test the position = 0, but upon the first occurence of the for-each its already too late. This is a once-off text so I can't combine it with other xslt templates that are already inside the xsl file. Thanks.

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  • A really smart rails helper needed

    - by Stefan Liebenberg
    In my rails application I have a helper function: def render_page( permalink ) page = Page.find_by_permalink( permalink ) content_tag( :h3, page.title ) + inline_render( page.body ) end If I called the page "home" with: <%= render_page :home %> and "home" page's body was: <h1>Home<h1/> bla bla <%= render_page :about %> <%= render_page :contact %> I would get "home" page, with "about" and "contact", it's nice and simple... right up to where someone goes and changes the "home" page's content to: <h1>Home<h1/> bla bla <%= render_page :home %> <%= render_page :about %> <%= render_page :contact %> which will result in a infinite loop ( a segment fault on webrick )... How would I change the helper function to something that won't fall into this trap? My first attempt was along the lines of: @@list = [] def render_page( permalink ) unless list.include?(permalink) @@list += [ permalink ] page = Page.find_by_permalink content_tag( :h3, page.title ) + inline_render( page.body ) @@list -= [ permalink ] else content_tag :b, "this page is already being rendered" end end which worked on my development environment, but bombed out in production... any suggestions? Thank You Stefan

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  • How to extract a 2x2 submatrix from a bigger matrix

    - by ZaZu
    Hello, I am a very basic user and do not know much about commands used in C, so please bear with me...I cant use very complicated codes. I have some knowledge in the stdio.h and ctype.h library, but thats about it. I have a matrix in a txt file and I want to load the matrix based on my input of number of rows and columns For example, I have a 5 by 5 matrix in the file. I want to extract a specific 2 by 2 submatrix, how can I do that ? I created a nested loop using : FILE *sample sample=fopen("randomfile.txt","r"); for(i=0;i<rows;i++){ for(j=0;j<cols;j++){ fscanf(sample,"%f",&matrix[i][j]); } fscanf(sample,"\n",&matrix[i][j]); } fclose(sample); Sadly the code does not work .. If I have this matrix : 5.00 4.00 5.00 6.00 5.00 4.00 3.00 25.00 5.00 3.00 4.00 23.00 5.00 2.00 352.00 6.00 And inputting 3 for row and 3 for column, I get : 5.00 4.00 5.00 6.00 5.00 4.00 3.00 25.00 5.00 Not only this isnt a 2 by 2 submatrix, but even if I wanted the first 3 rows and first 3 columns, its not printing it correctly.... I need to start at row 3 and col 3, then take the 2 by 2 submatrix ! I should have ended up with : 4.00 23.00 352.00 6.00 I heard that I can use fgets and sscanf to accomplish this. Here is my trial code : fgets(garbage,1,fin); sscanf(garbage,"\n"); But this doesnt work either :( What am I doing wrong ? Please help. Thanks !

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  • StreamReader.EndOfStream produces IOException

    - by Ziplin
    I'm working on an application that accepts TCP connections and reads in data until an </File> marker is read and then writes that data to the filesystem. I don't want to disconnect, I want to let the client sending the data to do that so they can send multiple files in one connection. I'm using the StreamReader.EndOfStream around my outter loop, but it throws an IOException when the client disconnects. Is there a better way to do this? private static void RecieveAsyncStream(IAsyncResult ar) { TcpListener listener = (TcpListener)ar.AsyncState; TcpClient client = listener.EndAcceptTcpClient(ar); // init the streams NetworkStream netStream = client.GetStream(); StreamReader streamReader = new StreamReader(netStream); StreamWriter streamWriter = new StreamWriter(netStream); while (!streamReader.EndOfStream) // throws IOException { string file= ""; while (file!= "</File>" && !streamReader.EndOfStream) { file += streamReader.ReadLine(); } // write file to filesystem } listener.BeginAcceptTcpClient(RecieveAsyncStream, listener); }

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  • rails Rake and mysql ssh port forwarding.

    - by rube_noob
    Hello, I need to create a rake task to do some active record operations via a ssh tunnel. The rake task is run on a remote windows machine so I would like to keep things in ruby. This is my latest attempt. desc "Syncronizes the tablets DB with the Server" task(:sync => :environment) do require 'rubygems' require 'net/ssh' begin Thread.abort_on_exception = true tunnel_thread = Thread.new do Thread.current[:ready] = false hostname = 'host' username = 'tunneluser' Net::SSH.start(hostname, username) do|ssh| ssh.forward.local(3333, "mysqlhost.com", 3306) Thread.current[:ready] = true puts "ready thread" ssh.loop(0) { true } end end until tunnel_thread[:ready] == true do end puts "tunnel ready" Importer.sync rescue StandardError => e puts "The Database Sync Failed." end end The task seems to hang at "tunnel ready" and never attempts the sync. I have had success when running first a rake task to create the tunnel and then running the rake sync in a different terminal. I want to combine these however so that if there is an error with the tunnel it will not attempt the sync. This is my first time using ruby Threads and Net::SSH forwarding so I am not sure what is the issue here. Any Ideas!? Thanks

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  • Performing calculations by subsets of data in R

    - by Vivi
    I want to perform calculations for each company number in the column PERMNO of my data frame, the summary of which can be seen here: > summary(companydataRETS) PERMNO RET Min. :10000 Min. :-0.971698 1st Qu.:32716 1st Qu.:-0.011905 Median :61735 Median : 0.000000 Mean :56788 Mean : 0.000799 3rd Qu.:80280 3rd Qu.: 0.010989 Max. :93436 Max. :19.000000 My solution so far was to create a variable with all possible company numbers compns <- companydataRETS[!duplicated(companydataRETS[,"PERMNO"]),"PERMNO"] And then use a foreach loop using parallel computing which calls my function get.rho() which in turn perform the desired calculations rhos <- foreach (i=1:length(compns), .combine=rbind) %dopar% get.rho(subset(companydataRETS[,"RET"],companydataRETS$PERMNO == compns[i])) I tested it for a subset of my data and it all works. The problem is that I have 72 million observations, and even after leaving the computer working overnight, it still didn't finish. I am new in R, so I imagine my code structure can be improved upon and there is a better (quicker, less computationally intensive) way to perform this same task (perhaps using apply or with, both of which I don't understand). Any suggestions?

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  • curl halts script execution

    - by Funky Dude
    my script uses curl to upload images to smugsmug site via smugsmug api. i loop through a folder and upload every image in there. but after 3-4 uploads, curl_exec would fail, stopped everything and prevent other images from uploading. $upload_array = array( "method" => "smugmug.images.upload", "SessionID" => $session_id, "AlbumID" => $alb_id, "FileName" => zerofill($n, 3) . ".jpg", "Data" => base64_encode($data), "ByteCount" => strlen($data), "MD5Sum" => $data_md5); $ch = curl_init(); curl_setopt($ch, CURLOPT_POST, true); curl_setopt($ch, CURLOPT_RETURNTRANSFER, true); curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, 0); curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, 0); curl_setopt($ch, CURLOPT_POSTFIELDS, $upload_array); curl_setopt( $ch, CURLOPT_URL, "https://upload.smugmug.com/services/api/rest/1.2.2/"); $upload_result = curl_exec($ch); //fails here curl_close($ch); updated: so i added logging into my script. when it does fail, the logging stops after fwrite($fh, "begin curl\n"); fwrite($fh, "begin curl\n"); $upload_result = curl_exec($ch); fwrite($fh, "curl executed\n"); fwrite($fh, "curl info: ".print_r(curl_getinfo($ch,true))."\n"); fwrite($fh, "xml dump: $upload_result \n"); fwrite($fh, "curl error: ".curl_error($ch)."\n"); i also curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, 60*60);

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  • PHP manipulating multidimensional array values

    - by Joker
    I have a result set as an array from a database that looks like: array ( 0 => array ( "a" => "something" "b" => "something" "c" => "something" ) 1 => array ( "a" => "something" "b" => "something" "c" => "something" ) 2 => array ( "a" => "something" "b" => "something" "c" => "something" ) ) How would I apply a function to replace the values of an array only on the array key with b? Normally I would just rebuild a new array with a foreach loop and apply the function if the array key is b, but I'm not sure if it's the best way. I've tried taking a look at many array functions and it seemed like array_walk_recursive is something I might use, but I didn't have luck in getting it to do what I want. If I'm not describing it well enough, basically I want to be able to do as the code below does: $arr = array(); foreach ($result as $key => $value) { foreach ($value as $key2 => $value2) { $arr[$key][$key2] = ($key2 == 'b' ? $this->_my_method($value2) : $value2); } } Should I stick with that, or is there a better way?

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  • Instantiating and starting a Scala Actor in a Map

    - by Bruce Ferguson
    I'm experimenting with a map of actors, and would like to know how to instantiate them and start them in one fell swoop... import scala.actors.Actor import scala.actors.Actor._ import scala.collection.mutable._ abstract class Message case class Update extends Message object Test { val groupings = "group1" :: "group2" :: "group3":: Nil val myActorMap = new HashMap[String,MyActor] def main(args : Array[String]) { groupings.foreach(group => myActorMap += (group -> new MyActor)) myActorMap("group2").start myActorMap("group2") ! Update } } class MyActor extends Actor { def act() { loop { react { case Update => println("Received Update") case _ => println("Ignoring event") } } } } The line: myActorMap("group2").start will grab the second instance, and let me start it, but I would like to be able to do something more like: groupings.foreach(group => myActorMap += (group -> (new MyActor).start)) but no matter how I wrap the new Actor, the compiler complains with something along the lines of: type mismatch; found : scala.actors.Actor required: com.myCompany.test.MyActor or various other complaints. I know it must be something simple to do with anonymous classes, but I can't see it right now. Any suggestions? Thanks in advance!!

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  • Generate and merge data with python multiprocessing

    - by Bobby
    I have a list of starting data. I want to apply a function to the starting data that creates a few pieces of new data for each element in the starting data. Some pieces of the new data are the same and I want to remove them. The sequential version is essentially: def create_new_data_for(datum): """make a list of new data from some old datum""" return [datum.modified_copy(k) for k in datum.k_list] data = [some list of data] #some data to start with #generate a list of new data from the old data, we'll reduce it next newdata = [] for d in data: newdata.extend(create_new_data_for(d)) #now reduce the data under ".matches(other)" reduced = [] for d in newdata: for seen in reduced: if d.matches(seen): break #so we haven't seen anything like d yet seen.append(d) #now reduced is finished and is what we want! I want to speed this up with multiprocessing. I was thinking that I could use a multiprocessing.Queue for the generation. Each process would just put the stuff it creates on, and when the processes are reducing the data, they can just get the data from the Queue. But I'm not sure how to have the different process loop over reduced and modify it without any race conditions or other issues. What is the best way to do this safely? or is there a different way to accomplish this goal better?

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  • Is there a way to get number of connections in Signalr hub group?

    - by pajo
    Here is my problem, I want to track if user is online or offline and notify other clients about it. I'm using hubs and implemented both IConnected and IDisconnect interfaces. My idea was to send notification to all clients when hub detects connect or disconnect. By default when user refreshes page he will get new connection id and eventually previous connection will call disconnect notifying other clients user is offline even though he's actually online. I tired to use my own ConnectionIdFactory returning username for connection id but with multiple tabs opened at some point it will detect user connectionid disconnected and after that client side hub will try to unsuccessfully connect to the hub in endless loop wasting memory and cpu making browser almost unusable. I needed to fix it fast so I removed my factory and now I add every new connection to the group using username, so I can easily notify single user on all connections, but then I have problem of detecting if user is online or offline as I don't know how many active connection user is having. So I'm wondering is there a way to get number of connections in one group? Or if anybody has some better idea how to track when user goes offline? I'm using Signalr 0.4

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  • Evaluating Javascript Arrays

    - by FailBoy
    I have an array that contains an array of arrays if that makes any sense. so for example: [[1, 2, 3], [2, 3, 4], [3, 4, 5], [4, 5, 6]] I want to see whether an array exists withing the array, so if [1, 2, 3] is duplicated at all. I have tried to use the .indexOf method but it does find the duplicate. I have also tried Extjs to loop through the array manually and to evaluate each inner array, this is how I did it: var arrayToSearch = [[1, 2, 3], [2, 3, 4], [3, 4, 5], [4, 5, 6]]; var newArray = [1, 2, 3]; Ext.each(arrayToSearch, function(entry, index){ console.log(newArray, entry); if(newArray == entry){ console.log(index); }; }); This also does not detect the duplicate. the console.log will output [1, 2, 3] and [1, 2, 3] but will not recognize them as equal. I have also tried the === evaluator but obviously since == doesn't work the === wont work. I am at wits end, any suggestions.

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  • Grouping a list of of entities which has a sublist in c#

    - by mikei
    I have a set of Entities which basically has this structure. {Stats Name="<Product name> (en)" TotalResources="10" ..} {DayStats Date="2009-12-10" TotalResources="5"} {DayStats Date="2009-12-11" TotalResources="5"} {Stats} {Stats Name="<Product name> (us)" TotalResources="10" ..} {DayStats Date="2009-12-10" TotalResources="5"} {DayStats Date="2009-12-11" TotalResources="5"} {Stats} ... What I wan't to extract from this set is a new set entities (or entity in the example above) where the first level has been grouped by the (ignoring the country label) where all/some of the properties has been summmed together, including the the sublist of {DayStas} on a per day basis. So the result set of the example would look something like this: {Stats Name="<Product name>" TotalResources="20" ..} {DayStats Date="2009-12-10" TotalResources="10"} {DayStats Date="2009-12-11" TotalResources="10"} {Stats} ... So my question is: Is it possible to do this in a more elegant way in LINQ rather than the vanilla "loop-trhough-each-entity-and-compare"-way? And I wan't the set to contain the same type of entities as the original set ({Stats}, {DayStats}), your answer doesn't need to include code for that, I can probably work that out by myself. Just letting you know incase you need to take that into account. (I'm sorry if this question has been discussed before, I tried searching to no avail. I guess my searching skills are fuubar ;)) Merry christmas =)

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  • How do I get column names to print in this C# program?

    - by Kevin
    I've cobbled together a C# program that takes a .csv file and writes it to a datatable. Using this program, I can loop through each row of the data table and print out the information contained in the row. The console output looks like this: --- Row --- Item: 1 Item: 545 Item: 507 Item: 484 Item: 501 I'd like to print the column name beside each value, as well, so that it looks like this: --- Row --- Item: 1 Hour Item: 545 Day1 KW Item: 507 Day2 KW Item: 484 Day3 KW Item: 501 Day4 KW Can someone look at my code and tell me what I can add so that the column names will print? I am very new to C#, so please forgive me if I've overlooked something. Here is my code: // Write load_forecast data to datatable. DataTable loadDT = new DataTable(); StreamReader sr = new StreamReader(@"c:\load_forecast.csv"); string[] headers = sr.ReadLine().Split(','); foreach (string header in headers) { loadDT.Columns.Add(header); // I've added the column headers here. } while (sr.Peek() > 0) { DataRow loadDR = loadDT.NewRow(); loadDR.ItemArray = sr.ReadLine().Split(','); loadDT.Rows.Add(loadDR); } foreach (DataRow row in loadDT.Rows) { Console.WriteLine("--- Row ---"); foreach (var item in row.ItemArray) { Console.Write("Item:"); Console.WriteLine(item); // Can I add something here to also print the column names? } }

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  • Reducing Time Complexity in Java

    - by Koeneuze
    Right, this is from an older exam which i'm using to prepare my own exam in january. We are given the following method: public static void Oorspronkelijk() { String bs = "Dit is een boodschap aan de wereld"; int max = -1; char let = '*'; for (int i=0;i<bs.length();i++) { int tel = 1; for (int j=i+1;j<bs.length();j++) { if (bs.charAt(j) == bs.charAt(i)) tel++; } if (tel > max) { max = tel; let = bs.charAt(i); } } System.out.println(max + " keer " + let); } The questions are: what is the output? - Since the code is just an algorithm to determine the most occuring character, the output is "6 keer " (6 times space) What is the time complexity of this code? Fairly sure it's O(n²), unless someone thinks otherwise? Can you reduce the time complexity, and if so, how? Well, you can. I've received some help already and managed to get the following code: public static void Nieuw() { String bs = "Dit is een boodschap aan de wereld"; HashMap<Character, Integer> letters = new HashMap<Character, Integer>(); char max = bs.charAt(0); for (int i=0;i<bs.length();i++) { char let = bs.charAt(i); if(!letters.containsKey(let)) { letters.put(let,0); } int tel = letters.get(let)+1; letters.put(let,tel); if(letters.get(max)<tel) { max = let; } } System.out.println(letters.get(max) + " keer " + max); } However, I'm uncertain of the time complexity of this new code: Is it O(n) because you only use one for-loop, or does the fact we require the use of the HashMap's get methods make it O(n log n) ? And if someone knows an even better way of reducing the time complexity, please do tell! :)

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  • What does O(log n) mean exactly?

    - by Andreas Grech
    I am currently learning about Big O Notation running times and amortized times. I understand the notion of O(n) linear time, meaning that the size of the input affects the growth of the algorithm proportionally...and the same goes for, for example, quadratic time O(n2) etc..even algorithms, such as permutation generators, with O(n!) times, that grow by factorials. For example, the following function is O(n) because the algorithm grows in proportion to its input n: f(int n) { int i; for (i = 0; i < n; ++i) printf("%d", i); } Similarly, if there was a nested loop, the time would be O(n2). But what exactly is O(log n)? For example, what does it mean to say that the height of a complete binary tree is O(log n)? I do know (maybe not in great detail) what Logarithm is, in the sense that: log10 100 = 2, but I cannot understand how to identify a function with a logarithmic time.

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  • Casting to a struct from LPVOID - C

    - by Jamie Keeling
    Hello, I am writing a simple console application which will allow me to create a number of threads from a set of parameters passed through the arguments I provide. DWORD WINAPI ThreadFunc(LPVOID threadData) { } I am packing them into a struct and passing them as a parameter into the CreateThread method and trying to unpack them by casting them to the same type as my struct from the LPVOID. I'm not sure how to cast it to the struct after getting it through so I can use it in the method itself, i've tried various combinations (Example attatched) but it won't compile. Struct: #define numThreads 1 struct Data { int threads; int delay; int messages; }; Call to method: HANDLE hThread; DWORD threadId; struct Data *tData; tData->threads = numThreads; tData->messages = 3; tData->delay = 1000; // Create child thread hThread = CreateThread( NULL, // lpThreadAttributes (default) 0, // dwStackSize (default) ThreadFunc, // lpStartAddress &tData, // lpParameter 0, // dwCreationFlags &threadId // lpThreadId (returned by function) ); My attempt: DWORD WINAPI ThreadFunc(LPVOID threadData) { struct Data tData = (struct Data)threadData; int msg; for(msg = 0; msg<5; msg++) { printf("Message %d from child\n", msg); } return 0; } Compiler error: error C2440: 'type cast' : cannot convert from 'LPVOID' to 'Data' As you can see I have implemented a way to loop through a number of messages already, I'm trying to make things slightly more advanced and add some further functionality.

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  • Transfer data between C++ classes efficiently

    - by David
    Hi, Need help... I have 3 classes, Manager which holds 2 pointers. One to class A another to class B . A does not know about B and vise versa. A does some calculations and at the end it puts 3 floats into the clipboard. Next, B pulls from clipboard the 3 floats, and does it's own calculations. This loop is managed by the Manager and repeats many times (iteration after iteration). My problem: Now class A produces a vector of floats which class B needs. This vector can have more than 1000 values and I don't want to use the clipboard to transfer it to B as it will become time consumer, even bottleneck, since this behavior repeats step by step. Simple solution is that B will know A (set a pointer to A). Other one is to transfer a pointer to the vector via Manager But I'm looking for something different, more object oriented that won't break the existent separation between A and B Any ideas ? Many thanks David

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  • ASP.NET DropDownList posting ""

    - by Daniel
    I am using ASP.NET forms version 3.5 in VB I have a dropdownlist that is filled with data from a DB with a list of countries The code for the dropdown list is <label class="ob_label"> <asp:DropDownList ID="lstCountry" runat="server" CssClass="ob_forminput"> </asp:DropDownList> Country*</label> And the code that the list is Dim selectSQL As String = "exec dbo.*******************" ' Define the ADO.NET objects. Dim con As New SqlConnection(connectionString) Dim cmd As New SqlCommand(selectSQL, con) Dim reader As SqlDataReader ' Try to open database and read information. Try con.Open() reader = cmd.ExecuteReader() ' For each item, add the author name to the displayed ' list box text, and store the unique ID in the Value property. Do While reader.Read() Dim newItem As New ListItem() newItem.Text = reader("AllSites_Countries_Name") newItem.Value = reader("AllSites_Countries_Id") CType(LoginViewCart.FindControl("lstCountry"), DropDownList).Items.Add(newItem) Loop reader.Close() CType(LoginViewCart.FindControl("lstCountry"), DropDownList).SelectedValue = 182 Catch Err As Exception Response.Redirect("~/error-on-page/") MailSender.SendMailMessage("*********************", "", "", OrangeBoxSiteId.SiteName & " Error Catcher", "<p>Error in sub FillCountry</p><p>Error on page:" & HttpContext.Current.Request.Url.AbsoluteUri & "</p><p>Error details: " & Err.Message & "</p>") Response.Redirect("~/error-on-page/") Finally con.Close() End Try When the form is submitted an error occurs which says that the string "" cannot be converted to the datatype integer. For some reason the dropdownlist is posting "" rather than the value for the selected country.

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