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What is hashCode used for? Is it unique?
I notice there is a getHashCode() method in every controls, items, in WP7, which return a sequence of number. Can I use this hashcode to identify an item? For example I want to identify a picture or a song in the device, and check it whereabout. This could be done if the hashcode given for specifi...
Timer function to provide time in nano seconds using C++
I wish to calculate the time it took for an API to return a value.
The time taken for such an action is in the space of nano seconds. As the API is a C++ class/function, I am using the timer.h to caculate the same:
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How do I get Windows to go as fast as Linux for compiling C++?
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Unless a hardcore Windows systems hacker comes along, you're not going to get more than partisan comments (which I won't do) and speculation (which is what I'm going to try).
File system - You should try the same operations (including the dir) on the same filesystem...
What is the “N+1 selects problem” in ORM (Object-Relational Mapping)?
...bject-Relational mapping (ORM) discussions, and I understand that it has something to do with having to make a lot of database queries for something that seems simple in the object world.
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Is recursion ever faster than looping?
I know that recursion is sometimes a lot cleaner than looping, and I'm not asking anything about when I should use recursion over iteration, I know there are lots of questions about that already.
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Difference between Big-O and Little-O Notation
...you find a particular multiplier k for which the inequality holds beyond some minimum x.
In Little-o, it must be that there is a minimum x after which the inequality holds no matter how small you make k, as long as it is not negative or zero.
These both describe upper bounds, although somewhat co...
MongoDB Many-to-Many Association
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Depending on your query needs you can put everything in the user document:
{name:"Joe"
,roles:["Admin","User","Engineer"]
}
To get all the Engineers, use:
db.things.find( { roles : "Engineer" } );
If you want to maintain the roles in separate documents then you can include the document's...
Git commits are duplicated in the same branch after doing a rebase
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You should not be using rebase here, a simple merge will suffice. The Pro Git book that you linked basically explains this exact situation. The inner workings might be slightly different, but here's how I visualize it:
C5 and C6 are temporarily pulled out of dev
C7 is ...
Why is require_once so bad to use?
...em keeps a log of what's already been included/required. Every *_once call means checking that log. So there's definitely some extra work being done there but enough to detriment the speed of the whole app?
... I really doubt it... Not unless you're on really old hardware or doing it a lot.
If yo...
Why are elementwise additions much faster in separate loops than in a combined loop?
Suppose a1 , b1 , c1 , and d1 point to heap memory and my numerical code has the following core loop.
10 Answers
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