A question I got on my last interview:
Design a function f, such that:
f(f(n)) == -n
Where n is a 32 bit signed integer; you can't use complex numbers arithmetic.
If you can't design such a function for the whole range of numbers, design it for the largest range possible.
Any ideas?
I understand how to choose good file names, but what is the best convention? What would make searches faster and such. Should I use underscores or spaces? I'm using Windows 7 32 bit.
Also, with Windows 7 what are the restrictions on the size of file names? I occasionally get the "file path is too long" error.
I want to display a DIV inside a table cell which is too narrow for it. I'm using overflow:hidden to allow the div to spill out one side of the table cell but now I want to center it so that it spills out a wee bit on both sides insdead of alot on one side.
How do I horizontally center a DIV inside a TD which is too narrow for the DIV?
Hi,
I'm trying to read a file byte by byte, but I'm not sure how to do that. I'm trying to do it like that:
file = open(filename, 'rb')
while 1:
byte = file.read(8)
# Do something...
So does that make the variable byte to contain 8 next bits at the beginning of every loop? It doesn't matter what those bytes really are. The only thing that matters is that I need to read a file in 8-bit stacks.
I'm using the fragment identifier to create a permalink for AJAX events in my web app similar to this guy. Something like:
http://www.myapp.com/calendar#filter:year/2010/month/5
I've done quite a bit of searching but can't find a list of valid characters for the fragment idenitifer. The W3C spec doesn't offer anything.
Do I need to encode the characters the same as the URL in has in general?
There doesn't seem to be any good information on this anywhere.
I want to make a server written in C++ to power my game. I learned the basics of sockets and wrote a basic chat program that worked well. Now I want to create an HTTP server like Apache, but only for the AJAX request-response part.
I think just for the beginning i copied one Apache response text, and i sent the exact response with the C++ server program.
The problem that is that the browser (Firefox) connnects to the apache and everything works fine, except all of the requests get a correct response.
But if i send this with the C++ client, then FireBug tells me that the response status is OK (200) but there is no actual response text. (How is this possible?)
This response-text is exactly the same what apache sends. I made a bit-bit comparison and they were the same.
The php file wich is the original response
<?php echo "AS";echo rand(0,9); ?>
And the origional source code:
Socket.h http://pastebin.com/bW9qxtrR
Socket.cpp http://pastebin.com/S3c8RFM7
main.cpp http://pastebin.com/ckExuXsR
index.html http://pastebin.com/mcfEEqPP < this is the requester file.
ajax.js http://pastebin.com/uXJe9hVC
benchmark.js http://pastebin.com/djSYtKg9
jQuery is not needed.
The main.cpp there is lot of trash code like main3 and main4 functions, these do not affect the result.
I know that the response stuff in the C++ code is not really good because the connection closing is not the best; I will fix that later now I want to send a success response first.
UPDATE:
now i tested today a lot again and i find out there is no problem with the socket. I used the fiddler program to capture the the good answer and to capture the bad. They were the same. After this i turned off my socket application, and forced fiddler to auto respond, and the answer from the 'bad' answer still bat. So after that i replaced the bad with the good and nothing happedned. The bad answer with the good text still bad on the :8888 port but the other on the original :80 port was good, but they were absolutly the same and the same program sended it (fiddler) i think there is something missing if the response is not on the same server address (even not the same port).
UPDATE:
oh my god! i cant send ajax request to a remote server. now i know this.
I have a PHP MVC framework I've built from scratch which uses the traditional domain.com/controller/action URL routing. While I'm currently handling the below conversion in the router I'd like to replace them in the URL for cosmetic reasons.
For example:
controller/action?filter=bank
Becomes:
controller/action/filter/bank
I've done a bit of experimentation with a regex but can't seem to find a match. I'm also not sure how to rewrite it using RewriteCond.
Thanks in advance.
I'm a bit embarassed asking this here, but here goes:
I've got two tables, which you can see here:
http://img411.imageshack.us/img411/4562/query.jpg
I need to copy the effortid from the one table into the other, making sure that the values still maintain the correction relationships. The primary key for each is a combination of loggerid & datetime. What's the best way to do this?
Thanks in advance, and don't make fun :)
I have a dlg box as the main window. After a few searches on the we I tried downloading and running the sample the source here:
http://msdn.microsoft.com/en-us/magazine/cc164067.aspx
I get a compile error:
error C2440: 'static_cast' : cannot convert from 'UINT (__thiscall CStaticLink::* )(CPoint)' to 'LRESULT (__thiscall CWnd::* )(CPoint)'
1 Cast from base to derived requires dynamic_cast or static_cast
(VS 2008)
The tooltips functionality seems to be a bit of a challenge. Any suggestions on how to get this working are much appreciated.
I'm using my own SiteMapProvider which is just inherited and little bit rewritten System.Web.XmlSiteMapProvider.
I want to return different siteMapNode for clients and for managers. Or maybe the same but with different Title property.
Is it possible? If yes, how can I do that?
I have a few .Net projects that would benefit from using a document/object database opposed to a relational one. I think that db4o would be a good choice, but the $1200 commercial price tag is bit too much for us. I'd love to use MongoDb but it's design isn't for small scale, single server applications.
Are there other options out there that I just haven't run across for small scale applications?
I've noticed that PHPmyAdmin creates the following SQL for table creation:
CREATE TABLE something (
...
) auto_increment=1;
When I write a database creation script I don't use the auto_increment bit. From reading related questions here I understand that it determines the starting value for auto_increment values. But it is good practice to reset it to 1, or should I just leave it out of the SQL so that the default is used?
I am setting up some redirects. I want to redirect the following URL:
/cms/index.php?cat_id=2
to the following URL:
/flash-chromatography
The rule I currently have is as follows:
RewriteCond %{QUERY_STRING} ^cat_id=2$ [NC]
RewriteRule ^cms/index\.php$ /flash-chromatography [L,R=301]
This rule is almost perfect apart from it redirect the URL to the following:
/flash-chromatography?cat_id=2
So you see my problem is it has kept the ?cat_id=2 part when I don't want it to.
How do I stop it keeping this bit?
Hi
What language would I need to use to decompile an swf file automatically on my server, not like a desktop app.
A bit like http://www.showmycode.com/
And could anyone point me in the right direction to get started?
Is it possible to use CruiseControl.Net to set up a build farm? We currently have 4 different build machines building different things at different times and have a bit of a headache to manually balance the load somehow. I would prefer to designate one of them to be the master build machine, which would delegate work to the other ones when they are free.
I'm trying to optimize some bit packing and unpacking routines. In order to do the packing I need to calculate the number of bits needed to store integer values. Here is the current code.
if (n == -1) return 32;
if (n == 0) return 1;
int r = 0;
while (n)
{
++r;
n >>= 1;
}
return r;
Hi,on my 32-bit machine (with an Intel T7700 duo core), I have 15 precision digits for both double and long double types for the C language. I compared the parameters LDBL_DIG for long doubles and DBL_DIG for doubles and they are both 15. I got these answers using MVS2008. I was wondering if these results can be compiler dependent or do they just depend on my processor?
Thanks a lot...
Are there any security issues keeping the .NET PDB files on the real server?
I know that throwing exceptions might take a bit longer , but who throws exceptions during normal execution anyway? :-)
But from a security perspective? any issues?
What is a fast and efficient way to implement the server-side component for an autocomplete feature in an html input box?
I am writing a service to autocomplete user queries in our web interface's main search box, and the completions are displayed in an ajax-powered dropdown. The data we are running queries against is simply a large table of concepts our system knows about, which matches roughly with the set of wikipedia page titles. For this service obviously speed is of utmost importance, as responsiveness of the web page is important to the user experience.
The current implementation simply loads all concepts into memory in a sorted set, and performs a simple log(n) lookup on a user keystroke. The tailset is then used to provide additional matches beyond the closest match. The problem with this solution is that it does not scale. It currently is running up against the VM heap space limit (I've set -Xmx2g, which is about the most we can push on our 32 bit machines), and this prevents us from expanding our concept table or adding more functionality. Switching to 64-bit VMs on machines with more memory isn't an immediate option.
I've been hesitant to start working on a disk-based solution as I am concerned that disk seek time will kill performance. Are there possible solutions that will let me scale better, either entirely in memory or with some fast disk-backed implementations?
Edits:
@Gandalf: For our use case it is important the the autocompletion is comprehensive and isn't just extra help for the user. As for what we are completing, it is a list of concept-type pairs. For example, possible entries are [("Microsoft", "Software Company"), ("Jeff Atwood", "Programmer"), ("StackOverflow.com", "Website")]. We are using Lucene for the full search once a user selects an item from the autocomplete list, but I am not yet sure Lucene would work well for the autocomplete itself.
@Glen: No databases are being used here. When I'm talking about a table I just mean the structured representation of my data.
@Jason Day: My original implementation to this problem was to use a Trie, but the memory bloat with that was actually worse than the sorted set due to needing a large number of object references. I'll read on the ternary search trees to see if it could be of use.
The authlogic rails gem is doing a LOWER in the sql query.
SELECT * FROM `users` WHERE (LOWER(`users`.email) = '[email protected]') LIMIT 1
I want to get rid of the LOWER part since it seems to be slowing down the query by quite a bit.
I'd prefer to just lower the case in the code since this query seems to be expensive.
I'm not sure where to change this behavior in authlogic.
Thanks!
I'm using wx.AUI and having a bit of a problem managing panes. Once you have created a new pane using AddPane(), what is the syntax to update or change the pane?
I've seen the SetPane command but I can't find any examples. Can someone direct me to an example? Or perhaps it makes sense to use some command to delete the pane and create a new one?
Thanks in advance for your time.
Can anyone provide me with a script for creating a huge database (for example, 2 GB of data) in IBM Informix Dynamic Server (IDS) version 11.50.FC4 on a Linux RHEL 64-bit machine?
The .NET framework makes it easy to get information about various locales; the Win32 C++ APIs are a bit harder to figure out.
Is there an equivalent function in Win32 to get the two-letter ISO language name given an integer locale ID?
In C# I'd do:
System.Globalization.CultureInfo ci = new System.Globalization.CultureInfo(1034);
string iso = ci.TwoLetterISOLanguageName;
// iso == "es" now.