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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3
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2answers
918 views

Reverse horizontal and vertical for a HTML table

There is a two-dimensional array describing a HTML table. Each element of the array consists of: the cell content rowspan colspan Every row of this two dimensional array corresponds to <td> ...
2
votes
1answer
321 views

Approach to Authenticate Clients to TCP Server

I'm writing a Server/Client application where clients will connect to the server. What I want to do, is make sure that the client connecting to the server is actually using my protocol and I can ...
2
votes
4answers
371 views

Looking for monotonically increasing (integer) hash function

I'm looking for a HashFunction(X,Y: Integer): Integer that is monotonically increasing on X, then Y. So: HashFunction(x1,y1) > HashFunction(x2,y2) if x1>x2 HashFunction(x,y1) > HashFunction(x,y2) if ...
0
votes
0answers
87 views

Permission Management Algorithm

I have 3 levels of permission to see the product: Brand -> Allow/Deny Category -> Allow/Deny Product -> Allow/Deny For example, product A has: Category: Allow Product: Deny => product A cannot ...
0
votes
3answers
318 views

How to create single integer index value based on two integers where first is unlimited?

I have table data containing an integer value X ranging from 1.... unknown, and an integer value Y ranging from 1..9 The data need to be presented in order 'X then Y'. For one visual component I can ...
-1
votes
2answers
637 views

Accuracy in calculating distance from Android Device using double integral? [closed]

Using TYPE_LINEAR_ACCELERATION suppose I found out that the device is moving at 4 m/s². a(t)=s"(t)=+4 v(t)=∫4tdt s(t)=2/3t³ s(3)=18m How much accurate it would be?
2
votes
1answer
91 views

Finding the order of a set's elements

A little rephrased, in the form of a game, real-life problem: Suppose there is a set of elements {1, 2, ..., n}. Player A has chosen a single permutation of this set. Player B wants to find out the ...
-1
votes
3answers
1k views

Find all lines segments intersections

I have a collection of lines segments, represented by an array. Ex: [3,7,13,6,9] is 4 line segments: [(3,7)(7,13)] , [(7,13)(13,6)] , [(13,6)(6,9)] , ([6,9)(9,3)] I want to find all the lines ...
-1
votes
5answers
1k views

Reverse subarray of an array with O(1)

I have an idea how to implement sub array reverse with O(1), not including precalculation such as reading the input. I will have many reverse operations, and I can't use the trivial solution of O(N). ...
2
votes
0answers
125 views

Automatic Appointment Conflict Resolution

I'm trying to figure out an algorithm for resolving appointment times. I currently have a naive algorithm that pushes down conflicting appointments repeatedly, until there are no more appointments. ...
9
votes
1answer
214 views

“Bad apple” algorithm, or process crashes shared sandbox

I'm looking for an algorithm to handle the following problem, which I'm (for now) calling the "bad apple" algorithm. The problem I've got N processes running in M sandboxes, where N >> M. It's ...
1
vote
1answer
316 views

Operating systems theory — using minimum number of semaphores

This situation is prone to deadlock of processes in an operating system and I'd like to solve it with the minimum of semaphores. Basically there are three cooperating processes that all read data ...
2
votes
2answers
202 views

Effective and simple matching for 2 unequal small-scale point sets

I need to match two sets of 3D points, however the number of points in each set can be different. It seems that most algorithms are designed to align images and trimmed to work with hundreds of ...
0
votes
2answers
161 views

moore's law and quadratic algorithm

I was going thru a video (from coursera - by sedgewick) in which he argues that you cannot sustain Moore's law using a quadratic algorithm.He elaborates like this In year 197* you build a computer of ...
1
vote
2answers
3k views

Why does a proportional controller have a steady state error?

I've read about feedback loops, how much this steady state error is for a given gain and what to do to remove this steady state error (add integral and/or derivative gains to the controller), but I ...
0
votes
1answer
129 views

Calculating WPM given a variable stream of input

I'm creating an application that sits in the background and records all key presses (currently this is done and working; an event is fired every keydown/keyup). I want to offer a feature for the user ...
3
votes
1answer
87 views

An extensible logging architecture for Android?

The end goal is to have a variety of data sets that can all be graphically plotted against eachother. All data should correspond to a date, so that when plotted against each other, they show the ...
1
vote
1answer
191 views

Custom animation iOS

I have seen animation, and i can't figure out how to do something like in this video(youtube). I want to discuss how it's made. I don't think that they're using sprites. I have one idea how to do ...
6
votes
2answers
497 views

Finding the lowest average Hamming distance when the order of the strings matter

I have a sequence of binary strings that I want to find a match for among a set of longer sequences of binary strings. A match means that the compared sequence gives the lowest average Hamming ...
8
votes
1answer
901 views

Name of the Countdown Numbers round problem - and algorithmic solutions?

For the non-Brits in the audience, there's a segment of a daytime game-show where contestants have a set of 6 numbers and a randomly generated target number. They have to reach the target number using ...
2
votes
3answers
186 views

Algorithm to infer tag hierarchy

I'm looking for an algorithm to infer a hierarchy from a set of tagged items. E.g. if the following items have the tags: 1 a 2 a,b 3 a,c 4 a,c,e 5 a,b 6 a,c 7 d 8 d,f Then I can construct an ...
2
votes
1answer
152 views

content fingerprint algorithm

I have a database containing just simple URLs. It is as simple as it sounds for now and URL can link to a website or a document(i.e. anything parseable to text). Now I have a simple code which ...
2
votes
1answer
287 views

Algorithm to update priority ordered list where changing priority of an item is expensive

I am working against an API where I can add and update items in a list that is ordered by a priority field I can set (which need not be contiguous but must be a positive integer). Updating a list ...
-2
votes
1answer
9k views

Algorithm to create an TicTacToe game AI [closed]

What are the algorithms I could use to create an AI for the game TicTacToe. I have already used Alpha–beta pruning and Predictive modelling. What the other good Algorithms I can use to create this AI. ...
7
votes
3answers
1k views

What skills (technologies) get outdated slower? [closed]

It's a common knowledge that since the IT industry develops very quickly, most of the skills get outdated fairly rapidly: jQuery, .NET, Ruby on Rails, etc. They change all the time so that it is ...
3
votes
2answers
173 views

What would be the optimal way to solve a problem like this?

I have a problem where I have to change all the Xs in a 2D array into 0s, and I have to calculate the minimum steps (where a single step consists of changing an entire row or column) required to do ...
11
votes
2answers
808 views

Functional programming and stateful algorithms

I'm learning functional programming with Haskell. In the meantime I'm studying Automata theory and as the two seem to fit well together I'm writing a small library to play with automata. Here's the ...
4
votes
2answers
587 views

How much logic can be put into an object-pooling factory class before it does more harm than good?

The main language I'm interested in doing object pooling in is AS3, which is known to need it in many cases. In the past I've always made a brand new factory class for every type I was going to try ...
6
votes
1answer
2k views

Sleeping Barber Problem (with multiple barbers)

The Sleeping Barber Problem is a classical synchronization problem that many of you may be familiar with or at least heard of. It's based on the premise that a barber (a thread) sleeps when there ...
6
votes
1answer
480 views

How can a beginner develop an algorithm for this problem?

Before I'm flamed, I'm just a beginner in programming. I have been learning Python for about 1 week by myself. I have a real problem to solve: Goal: The fastest route through a pathway. Problem: ...
4
votes
2answers
552 views

Deduplication of complex records / Similarity Detection

I'm working on a project that involves records with fairly large numbers of fields (~15-20) and I'm trying to figure out a good way to implement deduplication. Essentially the records are people along ...
3
votes
1answer
227 views

How to solve binary labeling with graph cut?

Many literature references suggest that the binary labeling problem can be converted into a graph cut problem and solved with the max flow/min cut algorithm. I'm trying to understand the formulation ...
2
votes
4answers
896 views

Architecture strategies for a complex competition scoring system

Competition description: There are about 10 teams competing against each other over a 6-week period. Each team's total score (out of a 1000 total available points) is based on the total of its ...
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votes
3answers
3k views

Why are algorithms and data structures important? [duplicate]

It seems like a lot of university-level computer science programs and programmer job interviews focus heavily on algorithms and data structures. I'm curious as to why universities and employers put so ...
1
vote
1answer
111 views

Algorithm for determining the order of property resolution

I have a list of properties, that are bound to some string expression: property z, expression '[x] + [y]' property x, expression '[y] + 1' property y, expression '1' So to solve z, I need ...
2
votes
0answers
208 views

Generate complex (non-convex) polyhedron UV mapping

I need to find an approach to the problem of generating texture maps for non-convex polyhedrons without using a design tool like Maya. Specifically, I am mapping simulation results data onto a 3D ...
3
votes
2answers
596 views

Which of these two shuffle algorithms is more random?

Which of below two shuffle algorithms (shuffle1 and shuffle2) is more random? public final class Shuffle { private static Random random; public static void shuffle1(final Object[] array) { ...
53
votes
11answers
3k views

Writing my problem solving approach on paper?

I'm a freshman Computer Science student and we just started doing some actual projects in Python. I have found I'm very efficient when I use the pen and paper method that my professor suggested in ...
2
votes
1answer
244 views

Programming puzzle with constant selection

THE QUESTION: There is an event where there are N contestants. There are three tasks in the event: A,B,C (say). Each participant takes part in the events in the listed order: i.e a contestant must ...
2
votes
1answer
94 views

How to indicate reliability when reporting availability of competencies

We have employees with competencies: Pete Welder Carpenter Melissa Carpenter Assume they both work 40 hours/week, and have not yet been assigned work. We need to report the ...
0
votes
1answer
334 views

help in theory regarding prefix_suffix_set

I found this question at codility.com, but I don't understand the question. Can you help me figure out what do they want? I am more interested in the theory than a code. A non-empty zero-indexed ...
2
votes
1answer
118 views

Storing different algorithms and using them for demonstration

I have an app for creating simple graphs (the kind with vertices and edges) and then using different algorithms on them (BFS, DFS, topsort, Prim's etc) for demonstrating how they work. I'm now ...
3
votes
2answers
520 views

Breadth-first graph search problem

I thought I was doing breadth-first graph search correctly, but my instructor's grading script is telling me that my answer is incorrect. From the instructions: Consider a breadth-first graph ...
0
votes
1answer
128 views

Algorithm for compression of a dictionary (words and definitions)

The theoretical situation is this: Let's say that we have a digital dictionary (by which I mean a traditional list of words and definitions, not an associative array). For the sake of simplicity, ...
3
votes
3answers
564 views

Finding an object on an infinite line

Question: There is an infinite line. You are standing at a particular point you can either move 1 step forward or 1 step backward. You have to search for an object in that infinite line. Your object ...
2
votes
2answers
374 views

When is a code considered tight and how does it increase efficiency of the code?

I have read many times that insertion sort has tight code and hence the hidden constant factor in its asymptotic complexity is smaller. I just read yesterday that quick sort has tight code just like ...
3
votes
1answer
190 views

Algorithm to arrange objects so that the total length of edges between them is minimized?

We are given a list of edges between a set of N vertices. There are atmost three edges joining a vertex. We have to arrange all the vertices on a straight line with the positions numbered from 1 to N ...
5
votes
1answer
733 views

Hashing Algorithm: Deleting an element in linear probing

While using Linear probing method to implement hashing, when we delete and element, the position of the deleted element is declared as a tombstone/ mark it as deleted. Why can't we just shift all the ...
1
vote
4answers
276 views

Application qos involving priority and bandwidth

Our manager wants us to do applicaiton qos which is quite different from the well-known system qos. We have many services of three types, they have priorites, the manager wants to suspend low priority ...
2
votes
1answer
101 views

Sorting with continous input

I'm designing (not writing, yet) a task scheduler system for a complex video game. The rest of the program passes it objects containing a function and some metadata including an estimation of how much ...