In mathematics and computer science, an algorithm is an effective method expressed as a finite list of well-defined instructions for calculating a function. Algorithms are used for calculation, data processing, and automated reasoning.

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42 views

Polygon simplification that encloses original set of points

I have been trying to implement an optimization for 2D sprite rendering to fight the problem of limited fillrate on mobile devices. The idea is to render textured polygons instead of quads that will ...
2
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0answers
195 views

Find all paths in a tree type of structure

The language I am using is C#, but I am looking more for help with the algorithm more than I am concerned with which language. I have been trying to develop this algorithm for a while now and I can't ...
0
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2answers
298 views

How to approach hours forecasting

I need to forecast budgeted hours for 2 departments to help them schedule staff as currently the best they can do is just wing it. When we receive a job proposal I'll have the person submitting the ...
3
votes
1answer
180 views

Divide the world map into fixed sized blocks

I am developing an app where I need to divide the entire world map into fixed sized square blocks. For simplicity, think of it as a problem of dividing the google maps into a fixed sized block. I can ...
3
votes
1answer
91 views

Prorating a license (its expiry) dependent on feature add-ons

I've ran into a problem trying to calculate prorating of a service. Hoping to get some help/hint from the community. I apologize if this isn't the right place to ask this question - will appreciate ...
6
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1answer
142 views

Finding similar high dimensional vectors

I have two lists (sizes m and n) containing high dimensional bit-vectors. All vectors have the same number of dimensions and use Hamming distance as measure if distance. For each element in the first ...
0
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2answers
158 views

Optimization problem where to start, what algorithms to use? [closed]

I have an optimization problem and I was wondering where to start from to be able resolve it. I think it can be solved with an NP-complete algorithm but I am not sure where to start from. The problem ...
2
votes
2answers
77 views

Retrieving an incorrectly stored tree data structure

Way back in the hazy origins of our platform it was decided that we were going to need some hierarchical data structures stored in the RDBMS. The relationships between nodes were stored via a '...
2
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1answer
113 views

Improving sampling algorithm

I am having a bit of trouble designing a new feature at the moment. It is part of a resource management system. I was wondering if anyone has experience doing anything similar. I'll try to explain: ...
4
votes
1answer
189 views

JavaScript functional conversion from flat list to tree

I've been going through the RxJS tutorials http://reactivex.io/learnrx/. Almost all of the exercises involve moving from a hierarchical structure to a flat structure so I thought I'd try to do the ...
3
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0answers
65 views

Generate quantity distribution of objects to reach goal for each attribute

The Problem Suppose we are given a variable-length list of objects containing a fixed-length list of positive decimal numbers as attributes. JSON Example [ {a: 0.1, b: 0.6, c: 0.0}, {a: 1.0,...
4
votes
1answer
138 views

Name-Based Sorting Algorithms For Maximized Common Letters

I am attempting to write a program for a competition (we're allowed to consult Stack Exchange, as long as I'm not given physical code) that takes in a list of 5000 people's names (distributed fairly ...
1
vote
1answer
204 views

Algorithm to get all paths in a tree

I have a tree that has n-levels. For example here I have four levels: Each node has two children (except for the last one), however everyone except for the first and last node of each row has two ...
2
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1answer
138 views

Is this Red-Black tree insertion pseudocode from Introduction to Algorithms (CLRS) correct?

For the Red-black tree insertion fixup the book distinguishes between 6 cases, 3 of which are symmetric. The cases are (z is the node being inserted): Case 1: z's uncle is red Case 2: z's uncle is ...
8
votes
1answer
181 views

Algorithm to generate Edges and Vertexes outwards from origin with max multiplicity of 3

I am creating a 2d game for a website where the universe can grow extremely large (basically infinitely large). Initially, the universe is composed of 6 stars that are an equal distance from the ...
1
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3answers
159 views

Should I be using any algorithm to sort/find items, or use a language's built-in ways?

I'm currently a first semester IT student, and I'm wondering if it's better to write my method to find something e.g. in a C# List, or to use any built in method to do these, such as LINQ or .Find or ....
4
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4answers
325 views

How to design a function that takes a date and gives out a number between 1-6, always the same for all dates

As a part of an algorithm I'm making I need to make a function that takes the current date to a function and gives out a number between 1-6, and not the same number for two consecutive dates. And it ...
-2
votes
1answer
228 views

Create arithmetic expression from number using +-/* that equals target [duplicate]

For example, you are given the source 1234 and the target 24. The task is to use the standard arithmetic operators +-/* placed within source, without changing the order of the digits of source to ...
5
votes
2answers
148 views

Find path of steepest descent along with path length in a matrix

Came across this problem -- You are given a grid with numbers that represent the elevation at a particular point. From each box in the grid you can go north, south, east, west - but only if the ...
0
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1answer
270 views

What is a lattice parser?

My friend asked me for help with his task: "Redeem a lattice parser with any programming language" - the problem is that he can't clearly explain me how the lattice parser should work. I've tried to ...
7
votes
2answers
331 views

Efficient algorithm to merge n successive sorted arrays in place

I am developing an in-place sorting algorithm that leaves the array into a state where it is basically a succession of sorted subsequences of any size (most are bigger than log2(size(array))); then it ...
0
votes
1answer
142 views

Do you know the name of this algorithm? (cycle with history?)

Context : I'm a IT student who is trying to implement a small application for my family. Every year, we offer each other gifts. Each one of us pick a name of a family member in a hat, and have to ...
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0answers
45 views

Graph grouping with criteria

I start with a list of adjacent tetrahedra, where there are tight seals to one another along faces for two tetrahedra that are adjacent. The vertices belonging to these faces for both tetrahedra are ...
4
votes
1answer
79 views

How to generalize the planar case of the closest pair problem to d dimensions?

I'm trying to create a solution for the Closest pair problem using d-dimensional points. I've done a thorough search on google but it seems that there is no explanation for the d-dimensional case ...
3
votes
4answers
643 views

Which algorithm is performant for matrix multiplication of 4x4 matrices of affine transformations

I am wondering what is a good, performant algorithm for matrix multiplication of 4x4 matrices. I am implementing some affine transformations and I am aware that there are several algorithms for ...
4
votes
1answer
131 views

Single Source Shortest Path

In the lecture we are taught that we can solve All Pairs Shortest Path(APSP) with matrix multiplication. In APSP we are creating a distance table for all the distances between each nodes in the graph....
0
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0answers
71 views

Compute the permutations for a set of numbers and then run each to find every possible schedule that fits a client constraints

I am building a Java program that computes the permutations for a set of numbers and then runs each of those permutations to find every single possible schedule that fits a client constraints. The ...
2
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1answer
88 views

Algorithm for best subset of items

I have a matrix M with size NxN where each position M(i,j) is an integer representing the relationship between item i and j. If i and j are the same item then the positions M(i,j) and M(j,i) are 0. ...
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votes
3answers
141 views

Balanced folder increment

I want to map an integer (let's say 32bits) to a valid path. The integer is an autoincrement value stored in the database. I also don't want at any case any folder to have more than N subfolders. ...
3
votes
1answer
115 views

Finding xor sum in a tree

I was trying to solve this problem on hackerearth where you have a tree with values on each node and you have to answer queries that ask what is the xor sum between two nodes. Also, there are updates ...
9
votes
4answers
489 views

What is the most efficient way to store this data?

I am in charge of rewriting some old VB code. I understand how it works, but I feel like there is a far-more efficient way to do what they did. I just can't figure out what it is. Here is a contrived ...
0
votes
2answers
366 views

How to scramble a word, keeping first and last characters the same?

I have a task, which is to scramble a single word, whose size is greater than 3 letters. The scrambled word must not be equal to the original, and the first and last letters of the word must remain ...
14
votes
2answers
455 views

How to find hard to misspell given names?

Here is a question that I believe could be solved with some data mining and a sophisticated algorithm, but I don't quite know how. Any pointers as to what data sources to use and what algorithm to ...
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3answers
241 views

Data structure for sorting by multiple attributes

I have a list of integer pairs. The value of this list is the sum of the maximum values of each pair. For (0, 5) (20, 5) (6, 8) the value would be 5 + 20 + 8 = 33 Given a list like this,...
6
votes
1answer
170 views

Identifying plagiarized jokes? [closed]

I'd like to be able to identify duplicate jokes posted on a website. I can build up a reasonably large database of previously-posted jokes, and then I'd like to look at each new joke as it comes in ...
5
votes
1answer
237 views

Combinatorial Optimization: Filling a Bag with Sand

I have an interesting "real-world" combinatorial optimization problem that I need to solve programmatically, however I have yet been able to whiteboard a good strategy. The task is similar to the ...
5
votes
1answer
87 views

Finding the smallest sub-collection of sets that intersect to produce one element

I came up with a problem that's similar to the Set Cover problem but which I can't reduce down to any know problem. Does anyone have a good algorithm for solving this? Given a set of elements U = {1, ...
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1answer
102 views

Sorting an array based on another array's order, quickly [closed]

There are two arrays of maps. The first array contains maps of ID values in a specific order (but not necessarily either pure ASC or DESC ordering): // pseudo code first := [ {"id": 1}, {"...
2
votes
1answer
89 views

Using a user defined equation to compute an entire list of numbers and store the list in an array

A example of what I want to do: User puts numbers into a list on a GUI that looks like this | L1 | L2 | l3 | ---------------- | 3 | 6 | | | 5 | 3 | | ... He writes in a text area ...
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votes
2answers
110 views

creating a social trend algorithm [closed]

I want to try to create an algorithm that would rank links according to social trends. I've article links, I've their date of publishing. I also have data from Facebook: comments, shares, likes. My ...
-2
votes
1answer
751 views

Bresenham Vs Midpoint Circle drawing algorithm

Can somebody explain the difference between Bresenham and Midpoint Circle drawing algorithms? All I am able to understand is that in both algorithms we compute coordinates of an octant instead of ...
3
votes
1answer
173 views

Burrows-Wheeler transform backward search: how to find suffix index?

BWT backward search algorithm is pretty straightforward if we only need the multiplicity of a pattern. However I also need to find the suffix indices (i.e. positions in the reference string where a ...
5
votes
3answers
400 views

Comparing two large strings to see how much they match [duplicate]

Is there an easy way of comparing any two different size of string text to see how much percentage they're alike? I'm trying this but I'm running into to this issue below. The left text area is the ...
-3
votes
1answer
83 views

complexity of an algorithm, sorting 5% out [duplicate]

I have been asked the following question.. An algorithm considers n elements, sorts 5% of n out, considers the remain elements(95%), sorts 5% of the remain elements, and so on until finally one last ...
0
votes
2answers
376 views

What is this algorithm?

I would like to implement an algorithm but I guess it's a well-known problem and it has been implemented yet, but I am unable to verify that without its name. Here is what I am willing to do : I ...
1
vote
1answer
98 views

MInimum tree coverage

I would like to understand what would be the optimal method of finding minimum tree coverage of tree nodes. Let me explain. I have a self-referencing structure that represents a tree, with a limited ...
-1
votes
2answers
99 views

Permuting and combining the values based on the key

I am trying to generate a table which would show all possible combinations based on the key. To make it more clear lets say I have a kind of Key, Value pair set(Its mentioned kind of because there are ...
0
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0answers
156 views

How does postback url works in campaign tracking systems?

my question is theoretical, a vague idea or some sort of algorithm will be great. I am building an advertising campaign tracker web app for a friend, yet i am kinda lost, i cant figure out how the ...
3
votes
3answers
126 views

How to model heuristic uncertainty when sorting data?

Sorting algorithms assume you have a defined comparator. For example, if sorting integers A and B, the A > B operation allows you to determine if A should be after or before B. Imagine you want ...
0
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1answer
293 views

Laravel Algorithm for taxi app

I am trying to write a backend for a taxi service (university assignment) and I am stuck on the algorithm. whenever a new client posts a request, all the taxi drivers nearby get an email notification ...