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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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 ...
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1answer
75 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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127 views

Randomized Hash function with no collisions

Related to the question Which hashing algorithm is best for uniqueness and speed? Is there a way to create a hash function, or find one, whose hash length depends completely on the input length, has ...
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1answer
93 views

What is (or where can i find) the algorithm to decode FLAC to PCM?

I'm trying to program a very basic FLAC player using 100% C# completely from scratch. My understanding of this type of thing is very limited, so I'm using this project as a way to learn about ...
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1answer
101 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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1answer
245 views

What algorithm should I use to create an automatic staff scheduling feature?

Imagine a small local business (in my case a dog daycare) with a few dozen part-time employees . The goal is to automatically create weekly staff schedules. My question is about what algorithmic ...
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116 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: ...
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1answer
103 views

Practical Primes In P

Or rather, practically applying PRIMES in P. I've heard a lot about "PRIMES in P", or the "AKS algorithm". It is, to oversimplify slightly, a very fast way of finding prime numbers. However, while ...
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161 views

What's the algorithm of “Shuffle Mode” in audio/music players [closed]

I was researching on how is the "Shuffle mode" in music players implemented and what is the algorithm behind this. How it makes sure that any songs won't repeat? What's the most efficient algorithm ...
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1answer
112 views

Estimed number of tries

Problem: The Oscar Committee wants to decide which person should get the best actor award among the given N actors.For that they decided to use a random function random_bit() which returns either 0 ...
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3answers
1k views

Would using a hash table in garbage collection solve the stop the world problem of mark and sweep?

In mark-sweep-compact garbage collection algorithm you have to stop-the-world when relocating objects because reference graph becomes inconsistent and you have to replace values of all references ...
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4answers
227 views

The optimal recipe problem

Suppose I have a list of Ingredients In My Fridge which are going off soon, and a list of Recipes which use up various Ingredients. (Some of which I don't currently have.) Is there an algorithm which ...
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1answer
58 views

Difference in orientation of Sobel mask gives different edge detector result

I am implementing a Canny Edge detector for a class which I have based off the code found here. For the first derivative mask that I will convolve with the image, I am using the Sobel mask, although ...
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2answers
144 views

Search for the (slowly moving) number with penalty for too high test value

You task is to design a search algorithm that will find my secret number, which is between 0 and 2^64. If your test value is too low you can test again in 1 second. If your test value is too high you ...
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1answer
61 views

How can I approach creating an efficient algorithm for maximizing value with these specific constraints?

I'm having trouble coming up with an approach that isn't n^2 for this problem. Here's a contrived, simplified version I've come up with: Let's say you're a company that needs 4 employees to launch in ...
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1answer
190 views

Is there a purely SQL alternate to looping?

Historically, I probably would have written a script (php or something) to loop through all spreadsheet rows and perform some calculations. I'm looking for a pure SQL solution on the presumption ...
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31 views

Algorithm for inserting into sorted subset

A is a sorted list. B is a sorted list, and a subset of A. If an element is inserted into A at index i what's the most efficient way to determine the correct index i' for it's position in B? Given ...
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98 views

Why isn't there parallel reduction in the Standard Template Library?

Alexander Stepanov stated in talks and interviews that his realization that eventually lead him to generic programming and the Standard Template Library, was from the case of the parallel reduction ...
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46 views

Algorithm to Select Sequential Subarrays from an Array

I solved my problem by using simple nested loops and comparisons but I'm wondering if there is a well known Selection Algorithm to solve my problem. Let's say I have an array such as [1, 10, 250, 9, ...
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80 views

Algorithm / working approach to get a random list of data

I am working on a android schedule app but that isn't matter , the problem is a algorithm / methodology so you are welcome to just write the pusedo code to answer. The data is like this Place ...
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2answers
151 views

Smallest and Largest contiguous repeating sub-sequence in a sequence

I am trying to solve a outdated quiz problem. I am tasked to find the smallest and largest contiguous sequence of repeating numbers in a larger sequence.e.g. ...
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1answer
76 views

Comparing absolute values when determining zero crossing in 2D image

I am trying to implement an algorithm for finding the zero crossing (check that the signs of all the entries around the entry of interest are not the same) in a two dimensional matrix, as part of ...
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0answers
36 views

Maximize the visibility of an ad to a maximum of people in an automatic advertising system

I have N different ads that I want to display at the same time to M people in an automatic advertising system. Some people will never see some ads because they only check some specific criteria on the ...
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3answers
227 views

How to implement a Weighted shuffle

I recently wrote some code that I thought very inefficient, but since it included only a few values, I accepted it. However, I'm still interested at a better algorithm for the following: A list of ...
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1answer
130 views

Euclidean Space Fully Connected Nondirectional Graph: Shortest Path to all nodes

So this may be a question that is born of my inability to properly express my intentions to Google. In a fully connected non-directional graph such that any three points can be properly represented ...
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1answer
104 views

Optimal movie schedule

Let's say Mr. A goes to cinema and he gets a movie schedule. There are N movies on the program today (1 < N < 50) and for every movie the time of the start and the time of the end are given in ...
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2answers
181 views

Given two sorted array in ascending order with same length N, calculate the Kth min a[i]+b[j]. Time complexity O(N)

Given two sorted array in ascending order with same length N, calculate the Kth min a[i]+b[j]. Time complexity O(N). Another variant of the question goes like this: given a matrix with sorted rows, ...
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3answers
323 views

Print bottom view of a binary tree

For a binary tree we define horizontal distance as follows: Horizontal distance(hd) of root = 0 If you go left then hd = hd(of its parent)-1, and if you go right then hd = hd(of its ...
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255 views

How to find number of points with same minimal distances on matrix

I'm trying to find the number of points in a matrix with the same minimal distances. Start with a MxN matrix, where M and N < 50000. There is given a set of fixed points, with their respective ...
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169 views

Solution Checker Algorithm for a Game

For the moment I'm strictly speaking in Pseudocode. I'd only like to see if i'm on the right track. The game I'm talking about is similar to a application called FLOW. In this game, you're given a ...
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1answer
353 views

Beginning Data Mining

For simplicity, my database has entities and transactions. Each transaction has a DateCreated and a foreign key to the entity. I'd like to have the ability to find entities that have had a recurring ...
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1answer
68 views

How can a route finding program avoid obstacles/locations when calculating routes? [closed]

Do you delete nodes from the underlying graph representation? Or is there a more elegant way to do it?
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22 views

Calculating combinations from categories

I'm trying to calculate every possible selection from different categories. 1 choice must be made from every category and the categories are always in the same order. I save a string where each ...
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1answer
182 views

How to create a some kind of value for sentences? [closed]

I want to identify most matching sentence using some pattern. That means by using java algorithm I want to create identical value for each sentences.Each sentence when entering to that algorithm can ...
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29 views

Readers Writers algorithm help - starvation and no starvation

I found this link, as an explanation of r/w problem - http://pages.cs.wisc.edu/~bart/537/lecturenotes/s7.html But, I'm having problems realizing is there any starvation present here and why? Also, if ...
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1answer
76 views

Difficulty implementing algorithms from abstract understanding [closed]

I've got decent programming experience for an undergraduate. I just started the study of algorithms. I read the description and saw visual examples that make perfect sense in my head. But when it ...
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0answers
116 views

How to extract the active code path from a complex algorithm

I have been puzzled lately by an intruiging idea. I wonder if there is a (known) method to extract the executed source code from a large complex algorithm. I will try to elaborate this question: ...
2
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2answers
91 views

Set distances algorithm question

I have multiple sets containing integers. An integer maybe present in one set or multiple sets. I would like to find/match the sets with the most common integers. Example s1 {1, 2, 3, 4} s2 {1, 3, 4, ...
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2answers
201 views

What is a O(n) algorithm to solve this puzzle?

We are going to hold a meeting where everybody will speak in clockwise direction around a table. There are n people with n spots. Each person has a position preference (e.g. some want to go first, ...
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1answer
42 views

How do I mutate a value in a genetic algorithm using Gaussian distribution?

I've been reading 'Introduction to Evolutionary Algorithms'. This method is stated, but not described, and I can't find anything more specific online. p44/45 of 2nd Ed for reference. "adding to the ...
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1answer
153 views

Heuristic Approach for Flexible DIFF Implementation

I have created a DIFF implementation to compare document revisions at work. It is based on An O(ND) Difference Algorithm and Its Variations. One thing that has become important is to take the list ...
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1answer
175 views

How to develop an algorithm for brute-forcing / backtracking?

As a beginner programmer, I don't know how to conceptually think about brute-forcing. My mind can't really fathom how to write code that will try every possibility. I have a problem that I want to ...
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1answer
135 views

LLVM case: is the success due to the algorithms? [closed]

I'm not sure if this is a subjective question, I hope not but I'm not proficient with LLVM so I'm just wondering: how come it's become so popular and so widespread used in the industry? Were the ...
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1answer
66 views

Efficient algorithm for joining sieves

I'm trying to find an efficient algorithm for the following algorithm. I have a sequence consisting of lists of indices denoting indices to be removed. The semantics are such that each sequence must ...
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4answers
205 views

Building complex algorithms with TDD

I'm trying to adopt TDD in my daily programming practice. I use it at work very effectively, but I'm having trouble with my personal projects where I'm using some complex algorithms. The particular ...
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2answers
223 views

Algorithm to order array

Take for example this input array: [2,7,1,4,9] For this input, I need to produce an array of total 23 elements which contains two elements of 2, seven elements of 7, one element of 1, four elements ...
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39 views

Algorithm for HIghest Local Alignment Score with a specific character match between two subsequences

I'm writing a code that identifies the highest-scoring local alignment between a substring X' of X and a substring Y' of Y that has at least one column in which a C from X' is aligned to a W from Y'. ...
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3answers
192 views

Least Change Problem with Thousands of Denominations

In a hypothetical economy there are currency units that can represent thousands of different values. So, for example there might be coins worth 1c, 3c, 5c, 7c, 7.5c, 80c, 8001.5c etc. Given a list of ...
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50 views

Looking for a Treemap tiling algorithm

I'm looking for an algorithm to convert a tree of data into a 2 dimensional treemap view. http://en.wikipedia.org/wiki/Treemapping I can do all the coloring in and drawing myself, but if there was ...
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2answers
124 views

Approach to coding algorithms to minimize rework [closed]

I find myself reworking my code quite a bit, especially when learning to write algorithms that involve keeping track of multiple attributes and labels. I feel that having the pseudo-code written up, ...