I have an application where users can: Write reviews about products Add comments to products Up / Down vote reviews Up / Down vote comments Every Up/Down vote is recorded in a db table. What i want to do now is to create a ranking of the most active users in the last 4 weeks. Of course good reviews should be weighted more than good ...
Evidently LINQ's "OrderBy" had originally been specified as unstable, but by the time of Orca it was specified as stable. Not all documentation has been updated accordingly - consider these links: Jon Skeet on OrderBy stability Troy Magennis on OrderBy stability But if LINQ's OrderBy is now "stable," then it means it is not using a ...
I have posted this question at MathOverflow.com as well. I am no mathematician and English is not my first language, so please excuse me if my question is too stupid, it is poorly phrased, or both. I am developing a program that creates timetables. My timetable-creating algorithm, besides creating the timetable, also creates a graph who...
If you needed a clean and consistent sandbox for pathfinding what would you use? I want to experiment with different pathfinding algorithms by sending virtual units (robots) around obstacles on a geometric plane. But I don't need a feature overkill like a game engine or Flash might have, just an animated report and native collision de...
I am dealing with a MySQL table here that is keyed in a somewhat unfortunate way. Instead of using an auto increment table as a key, it uses a column of decimals to preserve order (presumably so its not too difficult to insert new rows while preserving a primary key and order). Before I go through and redo this table to something more s...
I am a beginner to programming. Should I like learn them side by side ? Now that I know DS and Algorithms form the basis of programming..Should I learn them first ? I am confused. What should be my learning path ? I want to be a really good Java programmer. ...
I have a file containing data as follows 10 20 30 40 70 20 30 70 30 40 10 20 29 70 80 90 20 30 40 40 45 65 10 20 80 45 65 20 I want to remove all subset transaction from this file. output file should be like follows 10 20 30 40 70 29 70 80 90 20 30 40 40 45 65 10 20 80 Where records like 20 30 70 30 40 10 20 45 65 ...
Hello people! Since I'm beginner in J I've decided to solve a simple task using this language, in particular implementing the bubblesort algorithm. I know it's not idiomatically to solve such kind of problem in functional languages, because it's naturally solved using array element transposition in imperative languages like C, rather th...
I have an array with arrays in it, where I want to sort the outer arrays based on values in a specific column in the inner. I bet that sounded more than a bit confusing, so I'll skip straight to an example. Initial data: var data = [ [ "row_1-col1", "2-row_1-col2", "c-row_1-coln" ], [ "row_2-col1", "1-row_2-c...
I have a list of items I want to buy. The items are offered by different shops and different prices. The shops have individual delivery costs. I'm looking for an optimal shopping strategy (and a java library supporting it) to purchase all of the items with a minimal total price. Example: Item1 is offered at Shop1 for $100, at Shop2 fo...
Hello I am wondering what algorithm would be clever to use for a tag driven e-commerce enviroment: Each item has several tags. IE: Item name: "Metallica - Black Album CD", Tags: "metallica", "black-album", "rock", "music" Each user has several tags and friends(other users) bound to them. IE: Username: "testguy", Interests: "python", ...
I have below a function (from a previous question that went unanswered) that creates an array with n amount of values. The sum of the array is equal to $max. function randomDistinctPartition($n, $max) { $partition= array(); for ($i = 1; $i < $n; $i++) { $maxSingleNumber = $max - $n; $partition[] = $number = rand(1, $maxSingl...
I'm in startup of designing a client/server audio system which can stream audio arbitrarily over a network. One central server pumps out an audio stream and x number of clients receives the audio data and plays it. So far no magic needed and I have even got this scenario to work with VLC media player out of the box. However, the tricky ...
First of all this is not homework! My question is from the book: Algorithms in C++ third edition by Robert Sedgewick. There is given an array of size n by 2^n (two dimensional) and we should fill it with binary numbers of bits size exactly n. For example for n=5 the result will be: 00001 00010 00011 00100 00101 00110 00111 And s...
Today i listened a lecture about fenwick trees (binary indexed trees) and the teacher says than this tree is a generalization of interval and segment trees, but my implementations of this three data structures are different. Is this afirmation true? and Why? ...
i have here a device which can give me gps coordinates. the time intervall i can define. i want to use it to calculate the average speed during driving or travelling by car. actually i used a orthodrome formula to calculate the distance between two points and then divided it by the given time intervall. by the implemenation i followed th...
I am having a sorted list which is rotated and I would like to do a binary search on that list to find the minimum element. Lets suppose initial list is {1,2,3,4,5,6,7,8} rotated list can be like {5,6,7,8,1,2,3,4} Normal binary search doesn't work in this case. Any idea how to do this. -- Edit I have one another condition. What if th...
I want to save my objects according to a key in the attributes of my object in a sorted fashion. Later on I'll access these objects sequentially from max key to min key. I'll do some search tasks as well. I consider to use either AVL tree or RB Tree. As far as i know they are nearly equivalent in theory(Both have O(logn)). But in practi...
Hi. I have a bunch of names in alphabetical order with multiple instances of the same name all in alphabetical order so that the names are all grouped together. Beside each name, after a coma, I have a role that has been assigned to them, one name-role pair per line, something like whats shown below name1,role1 name1,role2 name1,role3 n...
I'm writing a game which uses 3D models to draw a scene (top-down orthographic projection), but a 2D physics engine to calculate response to collisions, etc. I have a few 3D assets for which I'd like to be able to automatically generate a hitbox by 'slicing' the 3D mesh with the X-Y plane and creating a polygon from the resultant edges. ...