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How to find the kth largest element in an unsorted array of length n in O(n)?
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This is called finding the k-th order statistic. There's a very simple randomized algorithm (called quickselect) taking O(n) average time, O(n^2) worst case time, and a pretty complicated non-randomized algorithm (called introselect) taking O(n) worst case time. There's some info on Wikipedia, bu...
Why do people use __(double underscore) so much in C++
I was having a look through some open source C++ code and notice a lot of double under scores where used in the code, mainly at the start of variable names.
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How to check if an NSDictionary or NSMutableDictionary contains a key?
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And what if the key does exist, but it's corresponding value is nil?
– Fyodor Soikin
May 6 '10 at 21:30
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Unique fields that allow nulls in Django
...trings are equal to empty strings for uniqueness checks, under both Django and database rules.
You can force the admin interface to store NULL for an empty string by providing your own customized model form for Foo with a clean_bar method that turns the empty string into None:
class FooForm(forms....
How can you make a custom keyboard in Android?
I want to make a custom keyboard. I don't know how to do it using XML and Java. The following picture is a model of the keyboard I want to make. It only needs numbers.
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Purpose of ESI & EDI registers?
What is the actual purpose and use of the EDI & ESI registers in assembler?
5 Answers
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How do I include a file over 2 directories back?
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@Brian Well, that’s nonsense, you’re comparing apples and oranges. You’re right that a define would be used here but (1) that wasn’t even remotely the question here. And (2) you’d still use a relative path in your define, Unless you actually hard-code the whole absolute se...
What is a word boundary in regex?
...g Java regexes in Java 1.6 (to parse numeric output, among other purposes) and cannot find a precise definition of \b ("word boundary"). I had assumed that -12 would be an "integer word" (matched by \b\-?\d+\b ) but it appears that this does not work. I'd be grateful to know of ways of matchi...
Why should I prefer to use member initialization lists?
... this case, the constructor for B will call the default constructor for A, and then initialize a.x to 3. A better way would be for B's constructor to directly call A's constructor in the initializer list:
B()
: a(3)
{
}
This would only call A's A(int) constructor and not its default constructo...
Evaluate expression given as a string
...ied. For example, if you have a pre-defined variable name equal to "David" and you reassign using eval(parse(text = "name") == "Alexander", you will get an error because eval & parse do not return an R expression that can be evaluated.
– Crt
Aug 1 '16 at 22...