Tagged Questions

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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12 views

Arduino ADC value and practices to store data to buffer

I'm writing Arduino application which has timer interrupt to acquire ADC value. Main loop has serial transmission procedure to send data from buffer. I'm not sure how to store data in buffer. Best ...
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0answers
39 views

Developing a “time scheduler” app [duplicate]

I need to develop an application to generate, given a set of preferences and constraints, a time schedule for employees. These tables can really get complex and they might need to take into account ...
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1answer
100 views

Is it possible to apply Master Theorem for finding the square and cube root

I was asked to calculate the running time of an algorithm which finds the square root and cube root of a given number. Is it possible to apply Master theorem with regards to this? First, I need to ...
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3answers
137 views

How would you go about compressing a list of integers that are non unique and retain the original order?

Let's start out with an example [1,1,1,5,3,1,1,2,78,2,3,1,1,...,1] As you can tell by the example, 1 is repeated a lot, but there will be outliers (like 78, and really anything that isn't 1). The ...
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0answers
11 views

A heuristic approach to Clique problem over undirected Graph

I'm trying to get all complete subgraph given a graph G. Needless to say it is an NP-problem complete: Clique_problem. I understand getting the full set is not possible in real time(since it'll take ...
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1answer
41 views

Shaping the row sums of a matrix

Given a d*n matrix filled with random data (floating point numbers), how can some restrictions be set on the row sums by only allowing reordering within a column? Typical values n : 10 - 1000 ...
3
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2answers
70 views

Process to generate hierarchical structure based on relational data?

I have a csv of employee ids, names, and a reference column with the id of their direct manager, say something like this emp_id, emp_name, mgr_id 1,The Boss,, 2,Manager Joe,1 3,Manager Sally,1 ...
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0answers
47 views

Solving a maze while getting treasure along the way [on hold]

(Moved from stackoverflow) My algorithms professor gave our group this programming assignment: The situation: Given an ascii 20x20 maze, some treasure, a start point, and an endpoint, find a valid ...
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4answers
135 views

Algorithm for a UI showing X percentage sliders whose linked values always total 100%

A system I'm building includes a set of UI sliders (the number varies) each with a scale of 0-100. By slider I mean a UI where you grab an element and drag it up and down, like a volume control. They ...
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0answers
29 views

Kth Optimal path in a matrix

I had the following question I was trying to solve: You are given a n*n matrix. Every cell of the matrix contain some value (positive). You are currently at (0,0) and you have to go to right ...
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1answer
48 views

Algorithm to “de-rasterize” a voxel image of a polyhedron

Rasterizing a polygon in this question consists of creating an array of binary pixels that "represent" the polygon. The reverse of this process is easy to approximate in linear time to the perimeter ...
3
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1answer
44 views

How to diversify an optimal solution set?

If given a list of players, their salaries, and their projections, one can easily find the top 'n' projected teams (where a team is a combination of players), such that every team is under the salary ...
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1answer
59 views

Sorting list and changing same values to nearly the same

I have a list of doubles that need to be sorted and changed so that there are no two numbers that are the same (difference smaller then 0.05) and I need to do it fast. I don't care about preserving ...
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3answers
125 views

Generate unique integer from two integers with algorithm

I am currently trying to come up with an algoritm which would take at least two numbers (say user IDs) and then come up with an unique number which is generated based on these two numbers. Each ...
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0answers
46 views

Calculating “instability score” for connection quality, programmatically

First of all, apologies if this is posted in the wrong site. I thought it is more suitable here than SO because the question is quite generic, more an algorithm question than a specific programming ...
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1answer
65 views

Data structures and algorithms for a directed rooted tree with inherited properties?

I need to represent a directed rooted tree in memory. The caveat is, that nodes have properties. And those properties are inherited (but not 100%) by the child nodes, recursively. What would be a ...
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65 views

Similar problem to word break

I have a list of strings say L and an array of words say A. I want to find a string from the list L that is a best match to a string created from the permutations of the words in the array. The ...
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0answers
33 views

What is the best way to sort strings with multiple words in each line and is separated by newline in Java? [migrated]

I have list of anime that i have watch uptill now and i want to sort them in alphabetical order. Below is the small example of how the list is and there are over 200 lines. I have stored all of them ...
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0answers
52 views

How to improve A* Algorithm where each child node costs marginally different

I have an A* algorithm with a heuristic to best guide the best path. The problem is that each node can have up to 240 children and each subsequent child also... So doing a breadth first approach is ...
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1answer
45 views

Algorithm for tiling a surface with no adjacent tiles

I am looking for an algorithm that does as follows: Given a 2D grid of X,Y and a number of tiles T, places a tile in each cell of the grid such that the surrounding tiles are not the same. This ...
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1answer
60 views

Finding common subsets in a list of sets

Let say I have a list of sets, defined like this (3 sets in this example) : A = [1, 2, 3, 4, 5] B = [4, 5, 6, 7, 8] C = [1, 2, 3, 4, 5, 6, 7, 8] Total number of elements defined in sets : 18 I'd ...
0
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1answer
67 views

How to decide in which language to write an algorithm that iterates through large amounts of data? [closed]

I am attempting to implement an algorithm that takes in a massive array of data, and iterates through each element in this array. For each element, it will either create an new array and put the ...
1
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1answer
73 views

Check word density within a document

Here is the situation: I have a Document(d) and a set of keywords (Set<String> keywords). I like to check the density of each words from set keywords with d. I have few solution but not really ...
1
vote
1answer
45 views

How to do “image shifting” faster?

I have a grayscale matrix (implemented as a simple array) to be shown on a display: line 1: | a | b | c | line 2: | d | e | f | a-f are grayscale values. This pattern has to be shifted by a ...
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5answers
4k views

Algorithms: How do I sum O(n) and O(nlog(n)) together?

I have the follow algorithm which finds duplicates and removes them: public static int numDuplicatesB(int[] arr) { Sort.mergesort(arr); int numDups = 0; for (int i = 1; i < arr.length; ...
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0answers
49 views

Algorithm recommendation for string classification [migrated]

I have numerous (hundreds to low-thousands) of pre-classified short strings of text, each string is just a few words long, some just a single word. The strings have been divided into a few dozen ...
1
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1answer
45 views

saving connectivity information in a nodes/edges network

I want to implement the A* algorithm. I have a network with Nodes and Edges, both are classes. Now, I am unsure how to approach the connectivity information. Should a node know which edges depart ...
0
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0answers
20 views

selecting area in array and expanding it to surroundings

I'm currently solving an algorithmic problem, but english is not my native language and I'm running into the limits of my language abilities when searching for reasonable solution. The problem: I ...
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2answers
106 views

Algorithm for figuring out the enemy flag's location in Stratego

I am currently programming a Stratego game in JavaScript, simply because I wanted to learn to use JavaScript while spending some time to keep my programming skills up to par. (My current work ...
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0answers
16 views

solving a number theoretical problem [migrated]

In mathematics, the greatest common divisor (gcd), also known as the greatest common factor (gcf), highest common factor (hcf), or greatest common measure (gcm), of two or more integers (at least one ...
0
votes
1answer
54 views

Are there any known file dispensing algorithms?

I wish to know if there are any known algorithms for dispensing a list of files for a specified maximum directory size (disc size for example), while attempting to keep output directories size close ...
16
votes
1answer
405 views

3d Packing algorithm for item's shipping

I've received a task to build a shipping estimative that suggests the best accomodation of goods on as few boxes as possible: There is a finite set of known retangular box sizes There are many ...
2
votes
1answer
106 views

Find n nodes farthest away from each other

I'm looking for an algorithm that gives me the n nodes that are the farthest away from each other. Can this be accomplished relatively efficiently? To clarify my question: I think of the problem as ...
4
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1answer
120 views

Understanding Boyer-Moore Algorithm

Edit: I've found the original publication. It seems to me that the original does not have a l′(i). But I could be wrong because the definition of rpr(i) is so obscure to me. I'm not sure how it makes ...
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3answers
141 views

The right algorithm to get perfect combination

I am working on a self-study project but I cannot come up with a reliable answer. Here is the deal: I start with 500cm sticks. I have orders from customers who want smaller sticks. I am willing to ...
1
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1answer
42 views

Create a collection with “average points” of N items from a pool with items of various points

Let's say I have a question pool to generate exams out of it. Each question contains a difficulty from 1 (hard) to 99 (easy). The questions are available in a hash / array (adapt to your favorite ...
3
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1answer
307 views

Accuracy of “calculator algorithms”

I am building a library class that provides functionality for mathematical operations on BigDecimals (and a few on BigIntegers). Now, BigIntegers are quite easy to master and pleasant to use. ...
3
votes
1answer
61 views

Derive subset with sum between two values

I have a set S of size n whose members each have associated with them a number in the range 0.00 to 1.00 inclusive. I want to select a subset T of size m with this property: the average of the ...
2
votes
3answers
80 views

recalculation model for GUIs

I often come across this problem. Say to have a form with some controls: A B C = A + B D E = C * 2 ONLY IF D==TRUE F G = A - F The user fills A, then B. The system calculates C. The user fills D ...
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0answers
59 views

Best algorithm to schedule events

I have a data set of talks to be given at a event which is given by the user. It is assumed that talks are always ending on time and there are two parallel events at the same time. Both start at the ...
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votes
1answer
76 views

Given a subset of numbers and subset of sums. Match the numbers to sums.(Harder than appears)

I found the question below on a forum board. I'm not sure what the most efficent solution is. I'm not sure this fits exact cover, and approaching it via exhaustive backtracking seems somewhat ...
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0answers
14 views

Print the longest common sequence [migrated]

I am trying to implement solution of the classical problem, but I am confused as I get some cases where I don't find good results. Output: "The Longest common sequence", "Length" def ...
2
votes
2answers
85 views

Algorithm for mapping users to a schedule based on time availability

I have a project where I must map employees to a schedule. The basic concept is: Company Opens between 08:30 and 17:00. Employee 1 can work from 08:30 to 12:00 then from 13:00 to 1700; Employee 2 ...
2
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1answer
94 views

What does 'upper bound' mean in context of BigO?

My computer science teacher says Big O has an upper bound but no lower bound. When I look at a graph of an algorithm mapped out using BigO though, there isn't an upper bound at all. The upper limit ...
0
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0answers
32 views

An algorithm to implement SQL's ORDER BY with TOP/LIMIT or OFFSET/FETCH

Is there a general algorithm to implement SQL's ORDER BY with OFFSET/LIMIT more efficiently than sorting all the records? The algorithm for a simple TOP x is easy enough. It takes one full pass ...
1
vote
1answer
151 views

Divide and Conquer Algorithm clarification needed

I have a homework assignment for a data structure/algorithm class. The task is to take an unsorted array of size n (example: [-8, 3, 2, -3, 3, 1, -3, -5]), and we have to use a divide and conquer ...
2
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1answer
151 views

Converting cron schedule to time intervals

I have, on the server, many jobs defined by users and some of those jobs are scheduled using cron expressions. I need to check (I can execute Groovy/Java on the server) if those jobs take longer than ...
0
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0answers
96 views

Tournament bracket customized algorithm

I'm in the making of a tournament for archery but i'm stuck because they want a specific match-matching for players. There is the usual 1-32,2-31,3-30 etc but the way they want the tree is a specific ...
3
votes
1answer
244 views

What makes for a bad case for quick sort?

I am learning about quicksort and want to illustrate different arrays that quicksort would have a hard time on. The quicksort I have in mind does not have an initial random shuffling, does 2 ...
1
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4answers
398 views

How to work around Java's lack of pointers to pointers when working with linked data structures? [closed]

I've learned from a textbook how to implement binary search trees recursively in Java, and am working on implementing them nonrecursively. I've found a simple and elegant way to implement an insert ...