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Search found 654 results on 27 pages for 'divide and conquer'.

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• Automatic people counting + twittering.

  - by c2h2

  Want to develop a system accurately counting people that go through a normal 1-2m wide door. and twitter whenever people goes in or out and tells how many people remain inside. Now, Twitter part is easy, but people counting is difficult. There is some semi existing counting solution, but they do not quite fit my needs. My idea/algorithm: Should I get some infra-red camera mounting on top of my door and constantly monitoring, and divide the camera image into several grid and calculating they entering and gone? can you give me some suggestion and starting point?

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• Grouping data into ranges in R

  - by Maddy

  supposing i have a data frame in R that has names of students in one column and their marks in another column. these marks range from 20 to 100. > mydata id name marks gender 1 a1 56 female 2 a2 37 male i want to divide the student into groups, based on the criteria of obtained marks, so that difference between marks in each group should be more than 10. i tried to use the function table, which gives the number of students in each range from say 20-30, 30-40, but i want it to pick those students that have marks in a given range and put all their information together in a group. any help is appreciated.

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• From Fraction to Decimal and Back?

  - by CC

  Hi folks... Is it possible to store a fraction like 3/6 in a variable of some sort? When I try this it only stores the numbers before the /. I know that I can use 2 variables and divide them, but the input is from a single text field. Is this at all possible? I want to do this because I need to calculate the fractions to decimal odds. A bonus question ;) - Is there an easy way to calculate a decimal value to a fraction? Thanks..

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• Reading files with Java

  - by sikas

  I would like to know how can I read a file byte by byte then perform some operation every n bytes. for example: Say I have a file of size = 50 bytes, I want to divide it into blocks each of n bytes. Then each block is sent to a function for some operations to be done on those bytes. The blocks are to be created during the read process and sent to the function when the block reaches n bytes so that I don`t use much memory for storing all blocks. I want the output of the function to be written/appended on a new file. This is what I've reached to read, yet I don't know it it is right: fc = new JFileChooser(); File f = fc.getSelectedFile(); FileInputStream in = new FileInputStream(f); byte[] b = new byte[16]; in.read(b); I haven't done anything yet for the write process.

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• Get n Number of words using regex in Java

  - by Aymon Fournier

  I have a section of a book, complete with punctuation, line breaks etc. and I want to be able to extract the first n words from the text, and divide that into 5 parts. Regex mystifies me. This is what I am trying. I creates an array of index size 0, with all the input text: public static String getNumberWords2(String s, int nWords){ String[] m = s.split("([a-zA-Z_0-9]+\b.*?)", (nWords / 5)); return "Part One: \n" + m[1] + "\n\n" + "Part Two: \n" + m[2] + "\n\n" + "Part Three: \n" + m[3] + "\n\n" + "Part Four: \n" + m[4] + "\n\n" + "Part Five: \n" + m[5]; } Thanks!

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• A little help with MVC

  - by s0mmer

  Hi everyone, I'm working on a cocoa app for syncing data between two folders. It have profiles (so you can have multiple setups) It's possible to analyze data It's possible to sync the data Im a little confused. First of all i cant really see where to have a model? And how many controller would you suggest? 1 WindowController or AnalyzeController, SyncController etc. Its quite a while since i have worked with MVC. I've read some articles but i'm missing concrete examples on how to divide it. Best regards.

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• What algorithm would you use to code a parrot?

  - by Phil H

  A parrot learns the most commonly uttered words and phrases in its vicinity so it can repeat them at inappropriate moments. So how would you create a software version? Assuming it has access to a microphone and can record sound at will, how would you code it without requiring infinite resources? The best I can imagine is to divide the stream using silences in the sound, and then use some pattern recognition to encode each one as a list of tokens, storing new ones as you meet them. Hashing the token sequences and counting occurrences in a database, you could build up a picture of the most frequently uttered phrases. But given the huge variety in phrases, how do you prevent this just becoming a huge list? And the sheer number of pairs to match would surely generate lot of false positives from the combinatorial nature of matching. Would you use a neural net, since that's how a real parrot manages it? Or is there another, cleverer way of matching large-scale patterns in analogue data?

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• Return segmented average from SQL Query?

  - by Guillaume Filion

  Hi, I measure the load on DNS servers every minute and store that into an SQL DB. I want to draw a chart of the load for the last 48 hours. That's 69120 (48*24*60) data points but my chart's only 800 pixels wide so to make things faster I would like my SQL query to return only ~800 data points. It's seems to me like a pretty standard thing to do, but I've been searching the web and in books for such a thing for a while now and the closest I was able to find was a rolling average. What I'm looking for a more of a "segmented average": divide the 69120 data points in ~800 segments, then average each segment. My SQL table is: CREATE TABLE measurements ( ip int, measurement_time int, queries int, query_time float ) My query looks like this SELECT ip, queries FROM measurements WHERE measurement_time>(time()-172800) Thanks a lot!

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• Threads in PHP.

  - by Muhammad Sajid

  Hello.. I am creating a web application using zend, here i create an interface from where user-A can send email to more than one user(s) & it works excellent but it slow the execution time because of which user-A wait too much for the "acknowledged response" ( which will show after the emails have sent. ) In Java there are "Threads" by which we can perform that task (send emails) & it does not slow the rest application. Is there any technique in PHP/Zend just like in Java by which we can divide our tasks which could take much time eg: sending emails. Thanks..

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• Setting html controller to right side in firefox extension

  - by Yashwant Kumar Sahu

  Hi Expert, I am creating Mozilla extension. Here I need to set button controller right side in extension. Here I divide XUL file to div element. I have take a main div element and inside this i have take two more inner div. Then I have set one inner div style property float:left; and another div style property float:right. But this is not helpful for me. Here I also set Button CSS style property float:right which is inside the div which have property float:right. Awaiting for your response. Thanks in advance

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• How Can I Implement This In Java?

  - by davit-datuashvili

  first of all i am doing programs in java language this code is merely taken from web site i have not question about divide and conqurer algorithms but about function and it's argument here is code of ternary search def ternarySearch(f, left, right, absolutePrecision): #left and right are the current bounds; the maximum is between them if (right - left) < absolutePrecision: return (left + right)/2 leftThird = (2*left + right)/3 rightThird = (left + 2*right)/3 if f(leftThird) < f(rightThird): return ternarySearch(f, leftThird, right, absolutePrecision) return ternarySearch(f, left, rightThird, absolutePrecision) i am not asking once again how implement it in java i am asking for example how define function?for example let y=x^+3 yes we can determine it as public static int y(int x){ return x*x+3; } but here return ternarySearch(f, leftThird, right, absolutePrecision) function f does not have argument and how do such?please help me

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• How to detect if breaking an edge will make a graph disjoint?

  - by the_graph_guy

  I have a graph that starts off with a single, root node. Nodes are added one by one to the graph. At node creation time, they have to be linked either to the root node, or to another node, by a single edge. Edges can also be created and deleted (one by one, between any two nodes). Nodes can be deleted one at a time. Node and edge creation, deletion operations can happen in any arbitrary order. OK, so here's my question: When an edge is deleted, is it possible do determine, in constant time (i.e. with an O(1) algorithm), if doing this will divide the graph into two disjoint subgraphs? If it will, then which side of the edge will the root node belong? I'm willing to maintain, within reasonable limits, any additional data structure that can facilitate the derivation of this information. Maybe it is not possible to do it in O(1), if so any pointers to literature will be appreciated.

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• Create categorial variable in R based on range

  - by Stedy

  I have a dataframe with a column of integers that I would like to use as a reference to make a new categorical variable. I want to divide the variable into three groups and set the ranges myself (ie 0-5, 6-10, etc). I tried cut but that divides the variable into groups based on a normal distribution and my data is right skewed. I have also tried to use if/then statements but this outputs a true/false value and I would like to keep my original variable. I am sure that there is a simple way to do this but I cannot seem to figure it out. Any advice on a simple way to do this quickly?

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• MSSQL / T-SQL : How to update equal percentages of a resultset?

  - by Kent Comeaux

  I need a way to take a resultset of KeyIDs and divide it up as equally as possible and update records differently for each division based on the KeyIDs. In other words, there is SELECT KeyID FROM TableA WHERE (some criteria exists) I want to update TableA 3 different ways by 3 equal portions of KeyIDs. UPDATE TableA SET FieldA = Value1 WHERE KeyID IN (the first 1/3 of the SELECT resultset above) UPDATE TableA SET FieldA = Value2 WHERE KeyID IN (the second 1/3 of the SELECT resultset above) UPDATE TableA SET FieldA = Value3 WHERE KeyID IN (the third 1/3 of the SELECT resultset above) or something to that effect. Thanks for any and all of your responses.

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• Breaking One Big Graphic of MutablePaths into CAShapeLayers

  - by StackOverFlowRider

  I have a class called GraphicView that takes a Graphic object and draws it in its drawRect method. This Graphic object is basically an array of mutablePaths that comprise an icon that I want drawn. For performance and other issues, I was thinking of taking this icon that is comprised of mutablePaths, and dividing it into a bunch of CAShapeLayers. I'm wondering is this possible? Considering the points for the mutablePaths of the icon are all interwoven together (ie the icon was initially an SVG file that I converted to code), is it possible to divide different parts of the icon into CAShapeLayers, and reassemble them all together when assigning to the views layer? If so how would it be done? If I assign them as sublayers to a CALayer or CAShapeLayer, will it understand to mesh them all together?

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• Does database affect classes?

  - by satyanarayana

  I had created one class User and UserDAOImpl class for querying DB using class User. As there is one table to be queried, these two classes are sufficient for me. What if there is a case where new fields are to be added to that one table is to be divided into 3 tables( user_info, user_profile and user_address) to store user? As new fields are added, I need to change classes User and UserDAOImpl, it seems these two are not sufficient. It seems database changes affect my classes. In this case, do I need to divide class User into 3 classes as tables are changes? Can any one suggest me how can I solve this without making too many changes?

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• Is catching NumberFormatException a bad practice?

  - by integeruser

  I have to parse a String that can assume hex values or other non-hex values 0xff, 0x31 or A, PC, label, and so on. I use this code to divide the two cases: String input = readInput(); try { int hex = Integer.decode(input); // use hex ... } catch (NumberFormatException e) { // input is not a hex, continue parsing } Can this code be considered "ugly" or difficult to read? Are there other (maybe more elegant) solutions? EDIT : I want to clarify that (in my case) a wrong input doesn't exist: i just need to distinguish if it is a hex number, or not. And just for completeness, i'm making a simple assebler for DCPU-16.

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• Improve disk read performance (multiple files) with threading

  - by pablo

  I need to find a method to read a big number of small files (about 300k files) as fast as possible. Reading them sequentially using FileStream and reading the entire file in a single call takes between 170 and 208 seconds (you know, you re-run, disk cache plays its role and time varies). Then I tried using PInvoke with CreateFile/ReadFile and using FILE_FLAG_SEQUENTIAL_SCAN, but I didn't appreciate any changes. I tried with several threads (divide the big set in chunks and have every thread reading its part) and this way I was able to improve speed just a little bit (not even a 5% with every new thread up to 4). Any ideas on how to find the most effective way to do this?

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• PHP: Iterate through folders and display HTML contends

  - by Mestika

  Hi, I’m currently trying to develop a method to get a overview of all my different web templates I’ve created and (legally) downloaded over the years. I thought about a displaying them like Wordpress is previewing it’s templates view a small preview windows, displaying the concrete file with styles and everything. How to divide them into rows and columns and create AJAX modal window open on preview and pagination and so on I believe I can manage, but it is the concept itself about iterate over several folders then find all index.htm / index.html pages and displaying them. I’ve not worked very much with directories in PHP and the only references and code stumps I’ve found so far is just to list all the files in a certain directory like, what it contains. I would be really grateful if someone knew about a script, a function, snippet or just could get me a nudge in the right direction to create such a (probably simple) preview function. Sincere Mestika

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• Double # showing 0 on android

  - by Dave

  I'm embarrassed to ask this question, but after 45 minutes of not finding a solution I will resort to public humiliation. I have a number that is being divided by another number and I'm storing that number in a double variable. The numbers are randomly generated, but debugging the app shows that both numbers are in fact being generated. Lets just say the numbers are 476 & 733. I then take the numbers and divide them to get the percentage 476/733 = .64 I then print out the variable and it's always set to 0. I've tried using DecimalFormat and NumberFormat. No matter what I try though it always says the variable is 0. I know there is something simple that I'm missing, I just can't find it =/.

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• C++ a map to a 2 dimensional vector

  - by user1701545

  I want to create a C++ map where key is, say, int and value is a 2-D vector of double: map myMap; suppose I filled it and now I would like to update the second vector mapped by each key (for example divide each element by 2). How would I access that vector iteratively? The "itr-second[0]" syntax in the statement below is obviously wrong. What would be the right syntax for that action? for(std::map<in, vector<vector<double> > > itr = myMap.begin(); itr != myMap.end();++itr) { for(int i = 0;i < itr->second[0].size();++i) { itr->second[0][i] /= 2; } } thanks, rubi

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• Dividing a list in specific number of sublists

  - by Surya

  I want to divide a list in "a specific number of" sublists. That is, for example if I have a list List(34, 11, 23, 1, 9, 83, 5) and the number of sublists expected is 3 then I want List(List(34, 11), List(23, 1), List(9, 83, 5)). How do I go about doing this? I tried grouped but it doesn't seem to be doing what I want. PS: This is not a homework question. Kindly give a direct solution instead of some vague suggestions.

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• How to find the remainder of large number division in C++?

  - by Beelzeboul

  Hello, I have a question regarding modulus in C++. What I was trying to do was divide a very large number, lets say for example, M % 2, where M = 54,302,495,302,423. However, when I go to compile it says that the number is to 'long' for int. Then when I switch it to a double it repeats the same error message. Is there a way I can do this in which I will get the remainder of this very large number or possibly an even larger number? Thanks for your help, much appreciated.

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• How to group rows into two groups in sql?

  - by user1055638

  Lets say I have such a table: id|time|operation 1 2 read 2 5 write 3 3 read 4 7 read 5 2 save 6 1 open and now I would like to do two things: Divide all these records into two groups: 1) all rows where operation equals to "read" 2) all other rows. Sum the time in each group. So that my query would result only into two rows. What I got so far is: select sum(time) as total_time, operation group by operation ; Although that gives me many groups, depending on the number of distinct operations. How I could group them only into two categories? Cheers!

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• How to algorithmically partion a keyspace?

  - by pbhogan

  This is related to consistent hashing and while I conceptually understand what I need to do, I'm having a hard time translating this into code. I'm trying to divide a given keyspace (say, 128 bits) into equal sized partitions. I want the upper bound (highest key) of each partition. Basically, how would I complete this? #define KEYSPACE_BYTE_SIZE 16 #define KEYSPACE_BIT_SIZE (KEYSPACE_BYTE_SIZE * 8) typedef struct _key { char byte[KEYSPACE_BYTE_SIZE]; } key; key * partition_keyspace( int num_partitions ) { key * partitions = malloc( sizeof(key) * num_partitions ); // ... }

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