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What would cause an algorithm to have O(log log n) complexity?
... 16
16 / 2 = 8
8 / 2 = 4
4 / 2 = 2
2 / 2 = 1
This process takes 16 steps, and it's also the case that 65,536 = 216.
But, if we take the square root at each level, we get
√65,536 = 256
√256 = 16
√16 = 4
√4 = 2
Notice that it only takes four steps to get all the way down to 2. Why is this?...
Javascript how to split newline
I'm using jquery, and I have a textarea. When I submit by my button I will alert each text separated by newline.
How to split my text when there is a newline?
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Moving average or running mean
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UPD: more efficient solutions have been proposed by Alleo and jasaarim.
You can use np.convolve for that:
np.convolve(x, np.ones((N,))/N, mode='valid')
Explanation
The running mean is a case of the mathematical operation of convolution. For the running mean, you slide a win...
How can I repeat a character in Bash?
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You can use:
printf '=%.0s' {1..100}
How this works:
Bash expands {1..100} so the command becomes:
printf '=%.0s' 1 2 3 4 ... 100
I've set printf's format to =%.0s which means that it will always print a single = no matter what argument it is given. Therefore it prints 100 =s.
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Is there a way to select sibling nodes?
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Well... sure... just access the parent and then the children.
node.parentNode.childNodes[]
or... using jQuery:
$('#innerId').siblings()
Edit: Cletus as always is inspiring. I dug further. This is how jQuery gets siblings essentially:
function getChildren(...
Fast permutation -> number -> permutation mapping algorithms
...you have n possibilities, so you can describe this with a number between 0 and n-1. For the position that the next element ends up at, you have n-1 remaining possibilities, so you can describe this with a number between 0 and n-2.
Et cetera until you have n numbers.
As an example for n = 5, consid...
Finding duplicates in O(n) time and O(1) space
...ns in O(N) time. A swap only occurs if there is an i such that A[i] != i, and each swap sets at least one element such that A[i] == i, where that wasn't true before. This means that the total number of swaps (and thus the total number of executions of the while loop body) is at most N-1.
The seco...
Maximum number of characters using keystrokes A, Ctrl+A, Ctrl+C and Ctrl+V
.... Then we iterate through for i up to n, doing two things: pressing A once and pressing select all + copy followed by paste j times (actually j-i-1 below; note the trick here: the contents are still in the clipboard, so we can paste it multiple times without copying each time). We only have to consi...
Remove all line breaks from a long string of text
...er to input a string of text into the console, but the string is very long and includes many line breaks. How would I take the user's string and delete all line breaks to make it a single line of text. My method for acquiring the string is very simple.
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sed or awk: delete n lines following a pattern
How would I mix patterns and numeric ranges in sed (or any similar tool - awk for example)? What I want to do is match certain lines in a file, and delete the next n lines before proceeding, and I want to do that as part of a pipeline.
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