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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longest list of words with matching start and end letters

My friend gave me a problem that he says is easy, but I can't figure out a good algorithm to use to do it. You are given an input of 100 random English words. You have to find the longest string of ...
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5answers
1k views

Algorithm for percentage without knowing total number

Suppose there are n lines for a hotline. Whenever a customer calls the hotline, the call is forwarded to one of the n lines. And I want to assign percentage of calling to each of the n lines. ...
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2answers
105 views

Trivially Sortable Encoding for Arbitrary-Precision Decimals

I'm looking for a reasonably(*) space-efficient way to encode arbitrary-precision decimals (e.g. BigDecimal), such that when sorting the bit-pattern of the encodings lexicographically, the numbers ...
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1answer
788 views

get all the combination of a given set of numbers [duplicate]

I m trying to get the possible combinations of a given set of numbers say for example 123 The possible combinations would be 123 132 213 231 312 321 For this i have written a code as below - ...
3
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1answer
236 views

Minimize travel distance of n people to n locations

The problem: Given the coordinates of N people on a regular 2-dimensional plane and N target points-of-interest (POI) on the same plane, determine the set of pairs of people and POIs that minimize ...
0
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1answer
789 views

Is Microsoft Solver capable of solving such complex scheduling problems

I'm writing a application that will decide the scheduling plan for a few dozen people according to their occupation (role) and availability (week day and hours). I've used a excel spreadsheet to help ...
2
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4answers
399 views

Is there any sorting algorithm which is not inherently sequential and is task distributable?

After googling for a couple hours, I came to a conclusion that all sorting algorithms are inherently sequential which can be data distributed but not task distributable. Is there any algorithm which ...
0
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0answers
40 views

Generating all the words accepted by a deterministic finite automaton [duplicate]

Imagine you've got a finite deterministic automaton A defining some finite regular language L, consisting of N words. The first question is: how would you determine the number of words N? Then, I ...
3
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1answer
131 views

Defining a random “safe” path for a game character

I am writing a game in Java and it can be likened to the recently popular game "Flappy Bird" in the sense that the character moves up and down and the users touch and must avoid the obstacles. The ...
2
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1answer
151 views

Random forest ML algorithm suitable for use on cluster based HPC?

I need help in identifying a better algorithm. I have developed a script using pythons scipy package to analyse a rather large model that I wish to solve. The model contains over 12GB of data ...
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5answers
2k views

Structuring database for multi-object “activity” and “following” functionalities

I am working on a web application which operate with different types of objects such as user, profiles, pages etc. All objects have unique object_id. When objects interact it may produce "activity", ...
8
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1answer
444 views

How do I efficiently store all OpenStreetMap data in an indexed way?

I have a PBF file that contains the following information about a country: Nodes, each with their own longitude, latitude and properties; used to store points in a 2D space. Ways, each with their ...
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2answers
68 views

Adding a minimum rectangle overlap threshold

I have a function that works perfectly for detecting whether or not r1 overlaps with r2: boolean overlaps( Rectangle r1, Rectangle r2 ) { return r1.x < r2.x + r2.width && r1.x + ...
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2answers
9k views

Which string search algorithm is actually the fastest?

I have been stuck for some time on which is the fastest string search algorithm, heard many opinions, but in the end I'm not sure. I have heard some people saying that the fastest algorithm is ...
0
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1answer
481 views

Algorithm to Copy data faster than windows default copy provider

I need an algorithm which can copy data(files/folder) from one place to another, faster than windows default copy/paste option. I'm working in vc++. Is there any algorithm by which I can do copy/paste ...
0
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1answer
216 views

How to create a scoring system with time and correct answers for a game?

o create a scoring system with time and correct answers for a game? up vote 0 down vote favorite I have a small mobile quiz game, which consists of 30 questions, and a timer which starts from 0 ...
0
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1answer
76 views

Matching weighted unbalanced Bipartite graph

I am looking for a way to solve an assignment problem, but I am having some problems finding the correct algorithm to use. I have 2 list of nodes A and B, and in my problem may the length of A not be ...
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3answers
80 views

Algorithm to reduce calls to mapping API

A random distribution of points lies on a map. This data lies behind an API, and I want to grab the complete set of points within a given bounding box. I can query the API with the bounding box and ...
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2answers
225 views

High-level strategy for distinguishing a regular string from invalid JSON (ie. JSON-like string detection)

Disclaimer On Absence of Code: I have no code to post because I haven't started writing; was looking for more theoretical guidance as I doubt I'll have trouble coding it but am pretty befuddled on ...
0
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1answer
68 views

Algorithm to measure how “diffused” 5,000 pennies are in an economy?

Please allow me to use this example/metaphor to describe an algorithm I need. Objects There are 5 thousand pennies. There are 50 cups. There is a tracking history (Passport "stamp" etc) that is ...
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0answers
577 views

Multidimensional multiple-choice knapsack problem: find a feasible solution

My assignment is to use local search heuristics to solve the Multidimensional multiple-choice knapsack problem, but to do so I first need to find a feasible solution to start with. Here is an example ...
3
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4answers
262 views

Indefinite loops where the first time is different

This isn't a serious problem or anything someone has asked me to do, just a seemingly simple thing that I came up with as a mental exercise but has stumped me and which I feel that I should know the ...
3
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2answers
329 views

Find points whose pairwise distances approximate a given distance matrix

Problem. I have a symmetric distance matrix with entries between zero and one, like this one: D = ( 0.0 0.4 0.0 0.5 ) ( 0.4 0.0 0.2 1.0 ) ( 0.0 0.2 0.0 0.7 ) ( 0.5 1.0 0.7 0.0 ) I would ...
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2answers
431 views

Efficient algorithm to find a the set of numbers in a range

If I have an array of sorted numbers and every object is one of the numbers or multiplication. For example if the sorted array is [1, 2, 7] then the set is {1, 2, 7, 1*2, 1*7, 2*7, 1*2*7}. As you can ...
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1answer
98 views

Algorithmic Forecasting and Pattern Recognition

Say a user could enter project data into my software. Each project has 2 variables "size" and "work" and they're related but the relationship is not known. Is there a way to programmatically determine ...
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2answers
68 views

Minimizing Average Pairwise Squared Euclidean Norm

I'm pretty new to programming and computer science, but I was wondering if there was any good way to approach the following problem: For a set of 2n points (not necessarily unique) in R^k (assume each ...
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3answers
351 views

How many copies are needed to enlarge an array?

I am reading an analysis on dynamic arrays (from the Skiena's algorithm manual). I.e. when we have an array structure and each time we are out of space we allocate a new array of double the size of ...
4
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1answer
135 views

Tail-recursive implementation of take-while

I am trying to write a tail-recursive implementation of the function take-while in Scheme (but this exercise can be done in another language as well). My first attempt was (define (take-while p xs) ...
4
votes
1answer
461 views

Writing a spell checker similar to “did you mean”

I'm hoping to write a spellchecker for search queries in a web application - not unlike Google's "Did you mean?" The algorithm will be loosely based on this: http://catalog.ldc.upenn.edu/LDC2006T13 ...
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1answer
462 views

What data structure is suitable for implementing dynamic huffman encoding and decoding on a piece of text?

Some pseudo code or resources will be appreciated.I was thinking if implementing it in form of a BST stored in an array. However,not all operations can be performed easily using this approach. I am ...
3
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1answer
157 views

How to avoid oscillation by async event based systems?

Imagine a system where there are data sources which need to be kept in sync. A simple example is model - view data binding by MVC. Now I intend to describe these kind of systems with data sources and ...
3
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1answer
3k views

Magic square check for N×N matrix with minimum complexity

Is there any algorithm that works better than O(n²) to verify whether a square matrix is a magic one (e.g. such as sum of all the rows, cols and diagonally are equal to each other)? I did see someone ...
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2answers
90 views

Algorithm for optimal combination of two variables

I'm looking for an algorithm that would be able to determine the optimal combination of two variables, but I'm not sure where to start looking. For example, if I have 10,000 rows in a database and ...
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5answers
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Algorithm for flattening overlapping ranges

I am looking for a nice way of flattening (splitting) a list of potentially-overlapping numeric ranges. The problem is very similar to that of this question: Fastest way to split overlapping date ...
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4answers
177 views

How can the following algorithm be optimized?

I am currently working on a tic tac toe auto-mover game. I have come upon a decent algorithm that allows the computer to easily build towards, and claim victory spots. The problem however is that when ...
2
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1answer
172 views

Maze generation given intersection tree

Background Information: I'm building a 2D maze generator. I have tried Prim's algorithm, Wilson's algorithm, and a recursive backtracker algorithm for generating my maze, however was not satisfied ...
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1answer
213 views

Algorithm for detecting windows in a room

I am dealing with the following problem and i was looking to write a Pseudo-code for developing an algorithm that can be generic for such a problem. Here is what i have come up with thus far. ...
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5answers
4k views

Improving performance for grepping over a huge file

I have FILE_A which has over 300,000 lines and FILE_B which has over 30 million lines. I created a Bash script that greps each line in FILE_A over in FILE_B and writes the result of the grep to a new ...
0
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1answer
38 views

What would be the most efficient way to reduce the complexity of a set of rotations to a cube?

Despite the long title, my question is fairly simple. Let's say you have a cube in 3D-space and you want to rotate it along the three axes based on the set of instructions provided by a user or ...
3
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1answer
3k views

Why is time complexity of k-way merge sort O(nk^2)?

I'm comparatively new to algorithm analysis and am taking a related course on coursera where I came accross k way merge sort. The time complexity of 2 way merge sort is n log2 n, of 3 way merge sort ...
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2answers
904 views

Ideal data structure for storing map data?

I was asked this in an interview test. I did okay on the test but didn't know enough to answer this question. I am curious to know what data structures I can use to query the data quickly. Basically ...
6
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1answer
500 views

Min cost concatenation alignment [closed]

I am doing a project on data mining. I have a very large string of size, say n and many small strings, l_1,l_2.. each of size at most m. I want to find the sequence of small strings such that their ...
2
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2answers
870 views

Find number of occurrence of a word in a 2D matrix of Characters

Given a two dimensional matrix of alphabets, search the given word in all directions. Below is an example to search for the word "TEAM": No of occurrences is 4 in matrix below. What is the best ...
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2answers
41 views

Fixed duration Jobs need to be scheduled across fixed number of queues

Say I have 9 jobs with estimates of how long they will take to complete, and 3 queues that process these jobs - this constitutes one batch. Note that all the jobs are allocated to a queue beforehand ...
0
votes
3answers
277 views

Find second largest element in a array?

The problem is to solve it in n+logn−2 (base 2) no of comparisons. My algorithm is taking some extra space less then (O(n*n)). How can i reduce this extra space without increasing the complexity. ...
1
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1answer
256 views

What is a good algorithm for tracing around the edge of a 2D polyline

If I have a polyline made up of any number of vertexes, what is an efficient algorithm for tracing around the boundary of this polyline? There are 4 situations to consider: The polyline does not ...
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3answers
123 views

Unique ID algorithm

I've got a route that contains objects. Each one has value 0 or 1. I need unique route ID which will identify any objects order. Currently I'm doing it using binary number that is converted to decimal ...
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1answer
339 views

Serpent Algorithm thats implement Cipher

How must i change the Standard Implemplementation of the Serpent Algorithm that i can use it with the javax.crypto.CipherInputStream or javax.crypto.CipherOutputStream? I must implement/extends the ...
0
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0answers
59 views

Algorithm to calculate scheduling of task list, check feasibility [duplicate]

Problem I am trying to figure out how to best calculate a schedule as well as to check if for a set of tasks it is even possible to create a valid schedule for the following situation. Tasks have ...
0
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2answers
167 views

Image coordinates calculation algorithm

I was looking at Jcrop library code for scaled image size calculation, but I couldn't clearly understand algorithm used in following function: ...