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• Is a python dictionary the best data structure to solve this problem?

  - by mikip

  Hi I have a number of processes running which are controlled by remote clients. A tcp server controls access to these processes, only one client per process. The processes are given an id number in the range of 0 - n-1. Were 'n' is the number of processes. I use a dictionary to map this id to the client sockets file descriptor. On startup I populate the dictionary with the ids as keys and socket fd of 'None' for the values, i.e no clients and all pocesses are available When a client connects, I map the id to the sockets fd. When a client disconnects I set the value for this id to None, i.e. process is available. So everytime a client connects I have to check each entry in the dictionary for a process which has a socket fd entry of None. If there are then the client is allowed to connect. This solution does not seem very elegant, are there other data structures which would be more suitable for solving this? Thanks

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• Handling text menu in Python

  - by PulpFiction

  Hi all. I am trying to create a text based menu in Python. Here is the code: #!/usr/bin/env python def testcaseOutput(): print '1. Add. 2. Subtract. 3. Divide. 4. Multiply' try: answer = int(raw_input('Enter a value (1 - 4) >. ')) except ValueError: print 'Invalid input. Enter a value between 1 -4 .' testcaseOutput() if answer in range(1, 5): return answer else: print 'Invalid input. Enter a value between 1 - 4.' testcaseOutput() My question: When the user enters an invalid input, i.e. not a number, I want this function to get called again. So I used the recursive approach which I think is bad design. I use that approach again in the if answer in range(1, 5). Is there any other way to handle this? I need the prompt called again when there is an invalid input. Also, is there any way I can club the two constraints: check whether input is a number and check whether the number is in the range(1,5) together? As you can see, I am checking that individually.

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• Haskell search an element on a List

  - by user1887556

  I want a function that changes (1 to 0) on a list, when number of 1's isn't even. I have done these functions: 1) Sees if the lines in a list are even or not: parityLine :: [[Int]] -> [Bool] parityLine [] =[] parityLine (x:xs) |sum(x) `mod` 2 == 0 = True:(parityLine(xs)) |otherwise = False:(parityLine(xs)) 2) Sum the corresponding elements on a list of lists: sumPositions :: [[Int]] -> [Int] sumPositions [] = [] sumPositions (x:xs) = foldl (zipWith (+)) (repeat 0) (x:xs) 3) Sees if the columns in a list are even or not: parityColumn :: [Int] -> [Bool] parityColumn [] = [] parityColumn (x:xs) |head(x:xs) `mod` 2 == 0 = True:parityColumn(xs) |otherwise = False:parityColumn(xs) 4) Does the operation or with two boolean lists: bol :: [Bool] -> [Bool] -> [[Bool]] bol [] _ = [] bol (x:xs) (y:ys)= (map (||x) (y:ys)):(bol xs (y:ys)) 5) Correct List: correct :: [[Int]] -> [[Bool]] correct [] = [] correct (x:xs)=(bol(parityLine (x:xs))(parityColumn(sumPositions(x:xs)))) So what I want is to alter the function correct to [[Int]]-[[Int]] that does this: My Int list(x:xs) With my correct function applied [[0,0,1,1], [[True,True,False,True], [1,0,1,1], [True,True,True,True], [0,1,0,1], [True,True,True,True] [1,1,1,1]] [True,True,True,True]] Now I can see that in the first line third column, False, so I have to correct that number 1 to have a number of 1's even. Result I want that function correct does: [[0,0,0,1], [1,0,1,1], [0,1,0,1], [1,1,1,1]] Thanks.

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• C#/DataSet: Create and bind a custom column/property in a DataSet`s DataTable in the XXXDataSet.cs

  - by msfanboy

  Hello, I have a DataSet with a DataTable having the columns Number and Description. I do not want to bind both properties to a BindingSource bound again to 2 controls. What I want is a 3rd column in the DataTable called NumberDescription which is a composition of Number and Description. This property is bound only to 1 control/BindingSource`s property not 2. There is the partial XXXDataSet.Designer.cs file and the partial XXXDataSet.cs file. Of course I have defined the public string NumberDescription {get (doing some checks here;set (doing also some checks here} in the XXXDataSet.cs file. But all this does not bind my new property/Column to the BindingSource the DataTable is bound to because the DataSet does not know the new column/property. To make this new property/column known I could add a new column to the DataTAble in the DataSet designer view naming it NumberDescription. At least I see know the new property in the listing of the BindingSource so I can choose it. But all that did not help?? So how do I do that stuff properly? Should I call the NumberDescription Property in the Number AND Description Property ?

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• Is there possible in clojure to make a deadlock (or anything bad case) using agents?

  - by hsestupin

  CLojure agents is powerful tool. So actions to the agents are asynchronously sent using functions "send" and "send-off". And in theory there couldn't appear something like deadlock. Is there possible to write some clojure code (for example invoking from some action another action to another agent) using agents in which we have some concurrency problem - it could be deadlock, race condition or anything else. (guys, i'm very sorry for my english)

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• Code Golf: Connecting the dots

  - by ChristopheD

  Description: The input are multiple lines (terminated by a newline) which describe a 'field'. There are 'numbers' scattered across this field: the numbers always start at 1 they follow the ordering of the natural numbers: every 'next number' is incremented with 1 every number is surrounded by (at least) one whitespace on it's left and right Task: Draw lines between these numbers in their natural order (1 -> 2 -> 3 -> ...N) with the following characteristics: replace a number with a '+' character for horizontal lines: use '-' for vertical lines: use '|' going left and down or right and up: / going left and up or right and down: \ Important note: When drawing lines of type 4 and 5 you can assume that : (given points to connect with coordinates x1, y1 and x2, y2) distance(x1,x2) == distance(y1,y2). Have a look at the examples to see where you should 'attach' the lines. It is important to follow the order in which the dots are connected (newer lines can be drawn over older lines). Sample input 1 9 10 8 7 6 5 11 13 12 3 4 14 15 16 1 2 Sample output 1 /+ / | / | +/ +--+ | +\ | \ | \+ /+ | / | /+-------------+/ +---+ / | +--+ | + | +--------------------------+ Sample input 2 4 2 3 5 6 1 8 7 Sample output 2 /+ / | / | / | /+------------------+/ +--------+\ / \ +/ +--------------------------------------+ Winner: shortest solution (by code count). Input can be read via command line.

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• PHP debugging or performance Hook

  - by Joshua

  In an interpreted language like PHP it is possible in theory to set up some sort of callback function that would be run indiscriminately after every line of code. I am wondering if such a thing exists in PHP or if such a thing could be accomplished in any way? Such a feature could be useful for diagnostics or performance tests. Does anyone know of such a mechanism in PHP?

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• Android Notepadv1 Tutorial - Persistent mNoteNumber?

  - by Chris L.

  So I did the Notepadv1 tutorial. It worked great. No problems. I would however like some explanation on why the mNoteNumber remembers the last number of the item I created. So the class starts as follows: public class Notepadv1 extends ListActivity { private int mNoteNumber = 1; That's fine, I understand that. The only other time the mNoteNumber variable is used is when you add an item it creates a note with that number and then increments it to the next number as follows: private void createNote() { String noteName = "Note " + mNoteNumber++; Those are the only two references to the variable mNoteNumber. When I press the Home button and then reopen the app, I add a new note but instead of adding a second "Note 1" it remembers that the last note I added as "Note 3" so it makes "Note 4". So I don't get it. Does Java/Android remember the last state of variables? If anyone could give me some explanation that would be great THANKS!

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• question about cryptography

  - by davit-datuashvili

  i have question can anybody give me link about cryptography with algorithms ? thanks i need it very much in general i am using java language also it is possible in c++ but heart of site should be methods and theory part

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• Create an Oracle function that returns a table

  - by Craig

  I'm trying to create a function in package that returns a table. I hope to call the function once in the package, but be able to re-use its data mulitple times. While I know I create temp tables in Oracle, I was hoping to keep things DRY. So far, this is what I have: Header: CREATE OR REPLACE PACKAGE TEST AS TYPE MEASURE_RECORD IS RECORD ( L4_ID VARCHAR2(50), L6_ID VARCHAR2(50), L8_ID VARCHAR2(50), YEAR NUMBER, PERIOD NUMBER, VALUE NUMBER ); TYPE MEASURE_TABLE IS TABLE OF MEASURE_RECORD; FUNCTION GET_UPS( TIMESPAN_IN IN VARCHAR2 DEFAULT 'MONTLHY', STARTING_DATE_IN DATE, ENDING_DATE_IN DATE ) RETURN MEASURE_TABLE; END TEST; Body: CREATE OR REPLACE PACKAGE BODY TEST AS FUNCTION GET_UPS ( TIMESPAN_IN IN VARCHAR2 DEFAULT 'MONTLHY', STARTING_DATE_IN DATE, ENDING_DATE_IN DATE ) RETURN MEASURE_TABLE IS T MEASURE_TABLE; BEGIN SELECT ... INTO T FROM ... ; RETURN T; END GET_UPS; END TEST; The header compiles, the body does not. One error message is 'not enough values', which probably means that I should be selecting into the MEASURE_RECORD, rather than the MEASURE_TABLE. What am I missing?

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• .NET Compact Framework app that will run on both Professional and Standard

  - by CJCraft.com

  Is there any guidance on creating apps that will run on both professional (touch-screen) and standard (non-touch-screen) devices. I have a simple application that is mostly text and buttons that in theory should be able to run on both professional and standard devices with little if any modification. It seems the IDE wants to make this hard to impossible, but I expect it to be possible. Any advice?

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• C code Error: free(): invalid next size (fast):

  - by user1436057

  I got an error from my code, but I'm not sure where to fix it. Here's the explanation of what my code does: I'm writing some code that will read an input file and store each line as an object (char type) in an array. The first line of the input file is a number. This number tells me how many lines that I should read and store in the array. Here's my code: int main(int argc, char *argv[]){ FILE *fp; char **path; int num, i; ... /*after reading the first line and store the number value in num*/ path = malloc(num *sizeof(char)); i=0; while (!feof(fp)) { char buffer[500]; int length = 0; for (ch = fgetc(fp); ch != EOF && ch != '\n'; ch = fgetc(fp)) { buffer[length++] = ch; } if(ch == '\n' && ch!= EOF){ buffer[length] = '\0'; path[i] = malloc(strlen(buffer)+1); strcpy(path[i], buffer); i++; } } ... free(path); } After running the code, I get this *** glibc detected *** free(): invalid next size (fast): I have searched around and know this is malloc/free error, but I don't exactly know to fix it. Any help would be great. Thanks!

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• How would I sort files to directories based on filenames?

  - by gnomed

  I have a huge number of files to sort all named in some terrible convention. Here are some examples: (4)_mr__mcloughlin____.txt 12__sir_john_farr____.txt (b)mr__chope____.txt dame_elaine_kellett-bowman____.txt dr__blackburn______.txt These names are supposed to be a different person (speaker) each. Someone in another IT department produced these from a ton of XML files using some script but the naming is unfathomably stupid as you can see. I need to sort literally tens of thousands of these files with multiple files of text for each person; each with something stupid making the filename different, be it more underscores or some random number. They need to be sorted by speaker. This would be easier with a script to do most of the work then I could just go back and merge folders that should be under the same name or whatever. There are a number of ways I was thinking about doing this. parse the names from each file and sort them into folders for each unique name. get a list of all the unique names from the filenames, then look through this simplified list of unique names for similar ones and ask me whether they are the same, and once it has determined this it will sort them all accordingly. I plan on using Perl, but I can try a new language if it's worth it. I'm not sure how to go about reading in each filename in a directory one at a time into a string for parsing into an actual name. I'm not completely sure how to parse with regex in perl either, but that might be googleable. For the sorting, I was just gonna use the shell command: `cp filename.txt /example/destination/filename.txt` but just cause that's all I know so it's easiest. I dont even have a pseudocode idea of what im going to do either so if someone knows the best sequence of actions, im all ears. I guess I am looking for a lot of help, I am open to any suggestions. Many many many thanks to anyone who can help. B.

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• ASP error 424 Object required

  - by jeff

  I've got a problem with the following code pasted below, the problem seems to be coming from the openastextstream this carries on from another question: Set str_text_stream = obj_file.OpenAsTextStream(ForReading, TristateUseDefault) response.Write "<table>" int_j = 0 int_x = 0 Err.number = 0 Do While Not str_text_stream.AtEndOfStream str_po_insert_sql = "INSERT into tbl_purchase_orders (purchase_order_number, purchase_order_vendor_number, purchase_order_vendor_name) " str_po_insert_sql = str_po_insert_sql & " VALUES (" str_line = str_text_stream.readline arr_line = Split(str_line, """,""", -1) if Ubound(arr_line) <> 2 then Response.write "<tr><td>The line " & str_line & " could not be imported.</td></tr>" int_x = 1 else int_y = Instr(arr_line(2), """,") - 1 str_field_0 = Replace(arr_line(0), """", "") str_field_0 = Replace(str_field_0, "'", "''") str_field_1 = Replace(arr_line(1), "'", "''") str_field_2 = Left(arr_line(2), int_y) str_field_2 = Replace(str_field_2, "'", "''") str_po_insert_sql = str_po_insert_sql & "'" & str_field_0 & "', '" & arr_line(1) & "', '" & str_field_2 & "')" rs_po_insert.Open str_po_insert_sql, dbConnection, 3 if Err.number <> 0 then Response.write "<tr><td>The line " & str_po_insert_sql & " was imported.</td></tr>" end if Err.number = 0 int_j = int_j + 1 end if loop data from test import: "4501366934","800002","Clancy Docwra Ltd",04/05/2010 00:00:00 "4501366935","800004","Clancy Docwra Ltd",04/05/2010 00:00:00 "4501366936","800004","Clancy Docwra Ltd",04/05/2010 00:00:00

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• Filling in uninitialized array in java? (or workaround!)

  - by AlexRamallo

  Hello all, I'm currently in the process of creating an OBJ importer for an opengles android game. I'm relatively new to the language java, so I'm not exactly clear on a few things. I have an array which will hold the number of vertices in the model(along with a few other arrays as well): float vertices[]; The problem is that I don't know how many vertices there are in the model before I read the file using the inputstream given to me. Would I be able to fill it in as I need to like this?: vertices[95] = 5.004f; //vertices was defined like the example above or do I have to initialize it beforehand? if the latter is the case then what would be a good way to find out the number of vertices in the file? Once I read it using inputstreamreader.read() it goes to the next line until it reads the whole file. The only thing I can think of would be to read the whole file, count the number of vertices, then read it AGAIN the fill in the newly initialized array. Is there a way to dynamically allocate the data as is needed?

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• Function Triggered before fadeOut(); is finished

  - by willmcneilly

  Hi I'm new to javascript/jQuery this really has me stumped. What I'm trying to achieve here is On toggling a#sameDayTab jquery will look for .changeAlert and fadeOut it's container div, when toggled again the div will fade in (this works well.) Each toggle will also call a function that tells me how many .changeAlert's are present on the page and updates the number appropriately in a span. The problem is when I first click the toggled anchor the number of visible should be 0 as the .changeAlert has been hidden by fadeOut instead it returns the number of classes present on page load this value never changes no matter how many times the toggle is activated. Any help greatly appreciated. function totalNumFares () { var n = $('.changeAlert:visible').size(); $('.numFares').replaceWith('<span class=\"numFares\">'+ n +'</span>'); } totalNumFares(); //Toggle On/off Same Day Connections $('a#sameDayTab').toggle(function() { $('.changeAlert').parent().parent().parent().parent().parent().fadeOut(); totalNumFares(); },function(){ $('.changeAlert').parent().parent().parent().parent().parent().fadeIn(); totalNumFares(); });

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• What are the latest tools that I can use to write a DSL (Domain-specific language) in 2009 Sep?

  - by servicesxiaodai

  I looked into Logix and EasyExtend for Python. Logix hasn't been around for a while and it failed to install on Python 2.6. EasyExtend's tutorial is hopeless, the code in the tutorial doesn't even work. I am looking for something so I can write my DSL. My DSL will be used as a research tool. And I don't want to spend time learning all that parsing and compiler theory.

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• Exception in the OnIdle event does not bubble up

  - by sthay

  On my main form, I subscribed to two events: Application.ThreadException and Application.Idle. In theory, any exception that is not caught should get bubbled up to the main form. However, this does not work if the exception happens in the OnIdle event. The system just crashes. Does anyone know how to solve this problem? Thanks so much.

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• Localization of icon and default screen in iPhone

  - by hgpc

  Can the app icon and default screen be localized in iPhone? Has anyone tried it? In theory it should be possible as they're just image resources, but I found no explicit mention of this in the documentation, and I wouldn't like to have my app rejected or failing for this.

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• calling a trim method in actionscript 2.0

  - by user151013

  Hi I Got a notnull function for a text field as below private function valStringNotNull( val:String ) :Boolean { if ( String(val).length <= 0 ) { _errorCode = "StringNull"; return false; } _errorCode = "NoError"; return true; } and this function is being called here var pCnt:Number = 0; _validateParams[pCnt++] = { type: "notNull", input: win.firstNameInput , isSendData:true, dataName:"firstName"}; _validateParams[pCnt++] = { type: "notNull", input: win.lastNameInput, isSendData:true, dataName:"lastName"}; _validateParams[pCnt++] = { type: "noValidation", input: roleCombo, isSendData:true, dataName:"role" }; Selection.setFocus(win.firstNameInput); and for the not null I defined this way private function validateCases ( param:Object ) :Boolean { _errorObj = param.input || param.input1; switch( param.type ) { case "notNull": return valStringNotNull( param.input.text ); break; } } but as you see as I defined the length should be greater than zero its taking even a space as an input and displaying blank white space in my text field so I got a trim function as below public function ltrim(input:String):String { var size:Number = input.length; for(var i:Number = 0; i < size; i++) { if(input.charCodeAt(i) > 32) { return input.substring(i); } } return ""; } and I need to call this trim function before my not null function so that it trims off all the leftside white space but as I am very new to flash can some one help me how to keep this trim function before the notnull function.Can some one please help me with this please

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• SLRequest return nil before block complete

  - by jaytr0n

  I'm having a little trouble thinking through this and deciding if it's a design flaw on my behalf or if I'm missing a piece that could make this work. Basically I'm using the new SLRequest to make a Twitter API call. After the data is returned, I'd like to put it into an object and return that object: -(AUDSlide *) getFollowerSlide { SLRequest *getRequest = [SLRequest requestForServiceType:SLServiceTypeTwitter requestMethod:SLRequestMethodGET URL:[NSURL URLWithString:[NSString stringWithFormat:@"https://api.twitter.com/1.1/followers/ids.json?user_id=%@", [[self.twitterAccount valueForKey:@"properties"] valueForKey:@"user_id"]]] parameters:nil]; getRequest.account = twitterAccount; AUDSlide *slide = [[AUDSlide alloc] init]; [getRequest performRequestWithHandler:^(NSData *responseData, NSHTTPURLResponse *urlResponse, NSError *error) { if ([urlResponse statusCode] == 200) { NSError *jsonError = nil; NSDictionary *list = [NSJSONSerialization JSONObjectWithData:responseData options:0 error:&jsonError]; NSLog(@"Number of Followers: %u", [[list objectForKey:@"ids"] count]); slide.title = @"Followers"; slide.number = [NSString stringWithFormat:@"%u",[[list objectForKey:@"ids"] count]]; } else{ slide.title = @"Error"; slide.number = [NSString stringWithFormat: @"E%u", [urlResponse statusCode]]; } }]; return slide; } Of course the slide is returned before the call is complete and returns a nil object. So I'm not sure if I should try to force this into a synchronous request (that seems like it could be a bad idea) or rethink the design. Does anyone have any advice?

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• SQL - Query to display average as either "longer than" or "shorter than"

  - by user1840801

  Here are the tables I've created: CREATE TABLE Plane_new (Pnum char(3), Feature varchar2(20), Ptype varchar2(15), primary key (Pnum)); CREATE TABLE Employee_new (eid char(3), ename varchar(10), salary number(7,2), mid char(3), PRIMARY KEY (eid), FOREIGN KEY (mid) REFERENCES Employee_new); CREATE TABLE Pilot_new (eid char(3), Licence char(9), primary key (eid), foreign key (eid) references Employee_new on delete cascade); CREATE TABLE FlightI_new (Fnum char(4), Fdate date, Duration number(2), Pid char(3), Pnum char(3), primary key (Fnum), foreign key (Pid) references Pilot_new (eid), foreign key (Pnum) references Plane_new); And here is the query I must complete: For each flight, display its number, the name of the pilot who implemented the flight and the words ‘Longer than average’ if the flight duration was longer than average or the words ‘Shorter than average’ if the flight duration was shorter than or equal to the average. For the column holding the words ‘Longer than average’ or ‘Shorter than average’ make a header Length. Here is what I've come up with - with no luck! SELECT F.Fnum, E.ename, CASE Length WHEN F.Duration>(SELECT AVG(F.Duration) FROM FlightI_new F) THEN "Longer than average" WHEN F.Duration<=(SELECT AVG(F.Duration) FROM FlightI_new F) THEN 'Shorter than average' END FROM FlightI_new F LEFT OUTER JOIN Employee_new E ON F.Pid=E.eid GROUP BY F.Fnum, E.ename; Where am I going wrong?

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• Functional Programming Equivalent of Design Patterns Book?

  - by JasonFruit

  Is there a functional-programming equivalent to the Gang of Four Design Patterns book? That is, is there a book that explains and gives examples of how commonly-needed code structures are implemented functionally? I think seeing that would give me a better idea of how to go about using in practice the functional concepts whose theory I understand.

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• Mysterious combination

  - by pstone

  I decided to learn concurrency and wanted to find out in how many ways instructions from two different processes could overlap. The code for both processes is just a 10 iteration loop with 3 instructions performed in each iteration. I figured out the problem consisted of leaving X instructions fixed at a point and then fit the other X instructions from the other process between the spaces taking into account that they must be ordered (instruction 4 of process B must always come before instruction 20). I wrote a program to count this number, looking at the results I found out that the solution is n Combination k, where k is the number of instructions executed throughout the whole loop of one process, so for 10 iterations it would be 30, and n is k*2 (2 processes). In other words, n number of objects with n/2 fixed and having to fit n/2 among the spaces without the latter n/2 losing their order. Ok problem solved. No, not really. I have no idea why this is, I understand that the definition of a combination is, in how many ways can you take k elements from a group of n such that all the groups are different but the order in which you take the elements doesn't matter. In this case we have n elements and we are actually taking them all, because all the instructions are executed ( n C n). If one explains it by saying that there are 2k blue (A) and red (B) objects in a bag and you take k objects from the bag, you are still only taking k instructions when 2k instructions are actually executed. Can you please shed some light into this? Thanks in advance.

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• Given a 2d array sorted in increasing order from left to right and top to bottom, what is the best w

  - by Phukab

  I was recently given this interview question and I'm curious what a good solution to it would be. Say I'm given a 2d array where all the numbers in the array are in increasing order from left to right and top to bottom. What is the best way to search and determine if a target number is in the array? Now, my first inclination is to utilize a binary search since my data is sorted. I can determine if a number is in a single row in O(log N) time. However, it is the 2 directions that throw me off. Another solution I could use, if I could be sure the matrix is n x n, is to start at the middle. If the middle value is less than my target, then I can be sure it is in the left square portion of the matrix from the middle. I then move diagnally and check again, reducing the size of the square that the target could potentially be in until I have honed in on the target number. Does anyone have any good ideas on solving this problem? Example array: Sorted left to right, top to bottom. 1 2 4 5 6 2 3 5 7 8 4 6 8 9 10 5 8 9 10 11

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