cycle | 易学教程

How long does the stream of Random().Next() take until it repeats?

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问题 Consider the .NET Random stream: var r = new Random(); while (true) { r.Next(); } How long does it take to repeat? 回答1: According to the documentation: Pseudo-random numbers are chosen with equal probability from a finite set of numbers. The chosen numbers are not completely random because a definite mathematical algorithm is used to select them, but they are sufficiently random for practical purposes. The current implementation of the Random class is based on Donald E. Knuth's subtractive

jquery cycle automatically fit to window width on resize

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If I resize the window and then refresh the slider and the images within will resize to match the browser width, however I need this to happen automatically on window resize.... how can this be done ?? http://subzerostudio.com/Clients/perkinreveller/test.html <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>Untitled Document</title> <script type="text/javascript" src="js/jquery.min.js"></script> <script type="text/javascript" src="js/jquery.cycle.all.latest.js"></script> <script type="text/javascript"> $(document).ready(function() { $('.slideshow')

Check if two arrays are cyclic permutations

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Given two arrays, how do you check if one is a cyclic permutation of the other? For example, given a = [1, 2, 3, 1, 5] , b = [3, 1, 5, 1, 2] , and c = [2, 1, 3, 1, 5] we have that a and b are cyclic permutations but c is not a cyclic permutation of either. Note: the arrays may have duplicate elements. The standard trick here is to concatenate one of the arrays with itself, and then try to find the 2nd array in the concatenated array. For example, 'a' concatenated with itself is: [1, 2, 3, 1, 5, 1, 2, 3, 1, 5] Since you do see 'b' in this array starting from the 3rd element then a and b are

Finding cycle of 3 nodes ( or triangles) in a graph

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I am working with complex networks. I want to find group of nodes which forms a cycle of 3 nodes (or triangles) in a given graph. As my graph contains about million edges, using a simple iterative solution (multiple "for" loop) is not very efficient. I am using python for my programming, if these is some inbuilt modules for handling these problems, please let me know. If someone knows any algorithm which can be used for finding triangles in graphs, kindly reply back. A million edges is quite small. Unless you are doing it thousands of times, just use a naive implementation. I'll assume that

Generating a random DAG

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问题 I am solving a problem on directed acyclic graph. But I am having trouble testing my code on some directed acyclic graphs. The test graphs should be large, and ( obviously ) acyclic. I tried a lot to write code for generating acyclic directed graphs. But I failed every time. Is there some existing method to generate acyclic directed graphs I could use? 回答1: I cooked up a C program that does this. The key is to 'rank' the nodes, and only draw edges from lower ranked nodes to higher ranked ones

How can I find the number of Hamiltonian cycles in a complete undirected graph?

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Can someone explain how to find the number of Hamiltonian cycles in a complete undirected graph? Wikipedia says that the formula is (n-1)!/2 , but when I calculated using this formula, K3 has only one cycle and K4 has 5. Was my calculation incorrect? Since the graph is complete, any permutation starting with a fixed vertex gives an (almost) unique cycle (the last vertex in the permutation will have an edge back to the first, fixed vertex. Except for one thing: if you visit the vertices in the cycle in reverse order, then that's really the same cycle (because of this, the number is half of what

Spinning progress bar in every listview item

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问题 I've been scratching my head over this for a long time now and searched for an answer without any luck! It seems to be trivial, but as far as I know, it isn't. I use a listview in my Android application where every item (view) displays a spinning ProgressBar before the content is loaded and displayed (the content is retrieved through http calls and json, so it may take a while to process). The problem is that the spinning progress bars rotates independently of each other, thus creating the

Perl - while (<>) file handling [duplicate]

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This question already has an answer here : Which file is Perl's diamond operator (null file handle) currently reading from? (1 answer) A simple program with while( <> ) handles files given as arguments ( ./program 1.file 2.file 3.file ) and standard input of Unix systems. I think it concatenates them together in one file and work is line by line. The problem is, how do I know that I'm working with the first file? And then with the second one. For a simple example, I want to print the file's content in one line. while( <> ){ print "\n" if (it's the second file already); print $_; } The diamond

Using jQuery's .each() function to attach a function to multiple slideshow containers

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I have very many small jQuery Cycle slideshow divs (containers) on a one-page website like <div class="foo bar" data-value="1000"> // data-value varies on each container <img src="directory/img_0.jpg" alt="img 0" /> <img src="directory/img_1.jpg" alt="img 1" /> <img src="directory/img_2.jpg" alt="img 2" /> </div> and want to cycle them all - with each slideshow div having a different data-value - without hard coding/repeating $(document).ready(function() { $('.foo.bar').cycle({ speed: 300, timeout: 6000, delay: $('.foo.bar').data('value') }); }); for all occurences of such slideshow div. How

Swift SpriteKit ARC for dummies

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I have been trying to wrap my head around strong reference cycles and I am struggling. I have been reading the documentation from apple and on some website and I feel like they dont really address my issues. I understand you have to use weak and unowned depending if the object can be nil or not. So say you have to 2 classes like this class Person { var dog: Dog? .... } class Dog { weak var person: Person? } that reference each other I know that one of them has to use weak/unowned. This is the classic example seen in most tutorials. I also have seen examples like this and they too make sense to