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What would cause an algorithm to have O(log log n) complexity?
...there are typically two main routes that will arrive at this runtime.
Shrinking by a Square Root
As mentioned in the answer to the linked question, a common way for an algorithm to have time complexity O(log n) is for that algorithm to work by repeatedly cut the size of the input down by some consta...
IOS 7 Navigation Bar text and arrow color
I want to set background for Navigation Bar to be black and all colors inside it to be white .
11 Answers
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How to SSH to a VirtualBox guest externally through a host? [closed]
...should have one interface already which is using NAT. Then go to the Network settings and click the Port Forwarding button. Add a new Rule. As the rule name, insert "ssh". As "Host port", insert 3022. As "Guest port", insert 22. Everything else of the rule can be left blank.
or from the command li...
Quick and easy file dialog in Python?
...riendly, especially because the user can't copy/paste the path. I would like a quick and easy way to present a file selection dialog to the user, they can select the file, and then it's loaded to the database. (In my use case, if they happened to chose the wrong file, it would fail parsing, and wo...
What is a mutex?
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When I am having a big heated discussion at work, I use a rubber chicken which I keep in my desk for just such occasions. The person holding the chicken is the only person who is allowed to talk. If you don't hold the chicken you cannot speak. You can only indicate tha...
How to detect which one of the defined font was used in a web page?
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I've seen it done in a kind of iffy, but pretty reliable way. Basically, an element is set to use a specific font and a string is set to that element. If the font set for the element does not exist, it takes the font of the parent element. So, wh...
Normal arguments vs. keyword arguments
How are "keyword arguments" different from regular arguments? Can't all arguments be passed as name=value instead of using positional syntax?
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How to count TRUE values in a logical vector
...ic way to count the number of TRUE values in a logical vector? I can think of two ways:
8 Answers
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sed one-liner to convert all uppercase to lowercase?
...pper case
$ tr '[:lower:]' '[:upper:]' < input.txt > output.txt
Works using GNU sed (BSD sed doesn't support \L \U):
# Converts upper to lower case
$ sed -e 's/\(.*\)/\L\1/' input.txt > output.txt
# Converts lower to upper case
$ sed -e 's/\(.*\)/\U\1/' input.txt > output.txt
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How to make return key on iPhone make keyboard disappear?
...wo UITextFields (e.g. username and password) but I cannot get rid of the keyboard when pressing the return key on the keyboard. How can I do this?
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