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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Making a sequence strictly increasing by joining neighboring numbers using the smallest number of moves

I've got a following problem to solve: You are given a list of positive integers [x_1;x_2;...;x_n]. You are allowed to change 2 integers standing next to each other to one equal to their sum. (So ...
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3answers
210 views

Test & remove, or always remove

I have a function to show or hide a certain UI control. In my example case below, the framework is jQuery I'm using for an event to show a tool tip that may fire a LOT (based on mouse movements) - but ...
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7answers
9k views

What methods are there to avoid a stack overflow in a recursive algorithm?

Question What are the possible ways to solve a stack overflow caused by an recursive algorithm? Example I'm trying to solve Project Euler problem 14 and decided to try it with a recursive ...
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3answers
422 views

How can I best study a problem to determine whether recursion can/should be used?

In some cases, I fail to see that a problem could be solved by the divide and conquer method. To give a specific example, when studying the find max sub-array problem, my first approach is to brute ...
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4answers
149 views

How to convert the following node evaluation procedure to a non recursive solution?

I have the following recursive method. It evaluates a node (that represent a logical expression), using deep first search traversal : EvaluateNode(Node node) { bool result; switch(node.Type) ...
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112 views

Difficulty finding a recursive starting point for an algorithm

I am a student at university taking an analysis of algorithms class, and this dynamic programming problem has me stumped. I can't figure out how exactly I should define my recursive algorithm. The ...
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2answers
57 views

Resolve dependencies using before-after constraints

What i would like to do is the following. (Not sure if this question should go to StackOverflow, or here) Consider a datastructure like this: interface IAction { IAction[] afterActions() ...
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1answer
80 views

What algorithm-family or problem-space description fits? Industrial process feeding ingredients to process

Our process continuously feeds (normally <= 8) ingredients from a choice of hundreds, using 3 feeders only. So if ingredient count X is > 3, 3 through X are stirred together in a batch process and ...
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1answer
103 views

Algorithm for merging multiple rows of data

I need an algorithm to merge multiple rows for data, where one column is the index column and if one or more rows have the same index value merge the column values into a single row, and lastly sort ...
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2answers
259 views
+50

Looking for a DP algorithm for a specific packing problem

I have the following problem to solve: Given a ferry with length d and a list of n cars conataining their length we must load the cars on the ferry in an order in which they appear in the list on 2 ...
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0answers
20 views

Listing all possible binary search trees [on hold]

I'm stuck trying to write a program that lists all possible binary search trees that has n values from 1 to n. I tried to solve it by recursively listing all subtrees, but have trouble implementing ...
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0answers
64 views

How to ensure that the Programmer is not reselling my App? [on hold]

I'm a teacher. I am paying a programmer to built my App to teach Spanish. I have created the whole App and every single functionality, activity, design, look, content, etc. The programmer I hire is ...
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1answer
114 views

Solving a Sudoku variant with an unknown element

I recently stumbled upon a special Sudoku variant and am now struggling to effectively solve it programatically. Consider the following initial 6x6 grid: The rules The red question mark is ...
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1answer
159 views

Efficient algorithm for Virtual Machine(VM) Consolidation in Cloud

PROBLEM: We have N physical machines(PMs) each with ram Ri, cpu Ci and a set of currently scheduled VMs each with ram requirement ri and ci respectively Moving(Migrating) any VM from one PM to ...
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4answers
6k views

Return random `list` item by its `weight`

I have, for example, this table +-----------------+ | fruit | weight | +-----------------+ | apple | 4 | | orange | 2 | | lemon | 1 | +-----------------+ I need to return random ...
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55 views

Finding all Triangular Hulls in a 2D Point Cloud

My question: Given a set of 2D points, enumerate all triples of points such that no other points is inside the triangle formed by those 3 points. I'm looking for something better than this: // The ...
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3answers
449 views

Need help identifying a league scheduling algorithm

I am trying to create a sports league scheduler. I am having trouble identifying an algorithm to help me efficiently fill in each slot. Sample data to build the schedule would be: 10 teams Each ...
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3answers
160 views

Situations when O(n^2) better than O(n*log(n)) [duplicate]

Is there any situation a sorting algorithm of time complexity O(n2) could be better than an O(n log(n)) sorting algorithm in any way?
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45 views

Closest Point to Moving Target

I have a target which is constantly moving, and only its current position is ever known. I have about one hundred objects surrounding it, also only who's current positions are ever known. I am ...
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2answers
141 views

Sudoku hidden sets algorithm

I am writing a solver for the game sudoku. I am trying to implement the hidden set check in it and I can't figure out a way to do it well. I need to find out if there is a set of cells of size N in ...
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0answers
31 views

PHP Based algorithms for research [closed]

I am PHP programmer (Experienced ). Now i want to research in PHP algorithms and want to write a paper on a specific PHP algorithm. I need help : From where to start. What should i do . Some ...
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2answers
93 views

Efficient method for finding closest point to a line segment from a set of points including line segment's vertices

Let's say I have a list of points (in my case, point objects in a Python implementation). I then have a line segment connecting two of these points. I want to know if there's a way to efficiently ...
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34 views

Binary Search scheme alteration [closed]

I'm having a bit of an issue with programming an algorithm..... below would involve some of the details of the assignment; now before you begin to say that I should actually attempt, in solving this ...
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4answers
180 views

Most efficient way to generate all descendents of all nodes in a tree

I'm looking for the most efficient algorithm to take a tree (stored as either a list of edges; OR as a list of mappings from parent node to a list of child nodes); and produce, for EVERY node, a list ...
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1answer
110 views

Genetic Algorithm's Tournament Selection limit to be selected

I started working again on a Genetic Algorithm and i'm trying a lot of operators and ways of selection. When I made the Tournament Selection , I noticed that it gets really easy to always get the top ...
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46 views

Even/Odd Positive/Negative Integer Determination in Turing [closed]

I'm writing a program for my comp. sci class where I have to determine if an inputted integer is even or odd, and if it is positive or negative. This is my code, var number_1: int loop put "Write a ...
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7answers
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Why is binary search,which needs sorted data, considered better than linear search?

I have always heard that linear search is a naive approach and binary search is better than it in performance due to better asymptotic complexity. But I never understood why is it better than linear ...
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1answer
95 views

Algorithm to assign edges to smallest possible polygons?

I'm designing a procedural city generator, and the first step of the generation process is the creation of city streets. These streets extend out in a straight line to a point, then they can either ...
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166 views

How do personal assistants typically generate sentences?

This is sort of a follow up to this question about NLG research directions in the linguistics field. How do personal assistant tools such as Siri, Google Now, or Cortana perform Natural Language ...
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1answer
63 views

How to remove a middle element from queue?

I had a question, about how to remove an element from middle of the queue , without disturbing the order of other elements. E.g. Queue before operation:- <| a b c d e |< Queue after ...
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2answers
73 views

Greedy algorithms - minimising “parentheses rotatons” in order to get a valid expression

I'm preparing for an exam on which there will be problems solvable by DP, greedy algorithms. And one of the problem is - given a string containing parentheses in no particular order return a minimum ...
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2answers
250 views

Algorithm for rating books: Relative perception [closed]

So I am developing this application for rating books (think like IMDB for books) using relational database. Problem statement : Let's say book "A" deserves 8.5 in absolute sense. In case if A is ...
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2answers
103 views

it is possible to implement keyloggers in java [closed]

I am researching on keyloggers and as a part of my research I would like to know if its possible to implement keyloggers in java edit * How can i create a keylogger in java or to be precise what ...
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2answers
2k views

Try to find a word in the dictionary that has most letters given

Given some random letters , For example "a,e,o,g,z,k,l,j,w,n" and a dictionary.Try to find a word in the dictionary that has most letters given I was going through some old interview questions and ...
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2answers
68 views

Method for determining if a line segment is an external edge of a Delauney triangulation?

I've created a Delauney triangulation of a set of points. Now I want to iterate over the triangulation and remove any line segments/edges on the exterior for which the following are true: The ...
3
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1answer
104 views

What algorithm can be used for a more complex version of the bin packing problem?

I'm currently developing a plugin for World of Warcraft in LUA to help optimize a recently introduced part of the game, namely Garrison missions. A Warcraft Garrison (basically a player fortress) has ...
2
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3answers
341 views

Best practices for geolocation

We are writing a flight search engine. We want to pre-fill the departure airport for mobile users with the closest one to their location. To do that, our plan is to Find a list of airports with ...
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0answers
17 views

What is an efficient method for retrieving a column from a 1D array? [migrated]

An example in any language would help, though in the end I am going to be using either Ruby or JavaScript/CoffeeScript. Basically, I have a 1D array of pixel values. For example, I have an array ...
0
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1answer
67 views

Find 'Connected Components' in undirected, unweighted graph coded as a 2d array

Given an undirected, unweighted graph coded as a 2d array, how can I find the number of different connected components? Example There is the following 2d array (I'm not putting any brackets to ...
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4answers
306 views

Why are return values from compare functions in many languages defined loosely?

Many languages define that compare functions should return ANY negative value, zero, or ANY positive value. Is there some reason that it shouldn't be clearly defined as -1 0 and 1? Does a wide range ...
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2answers
218 views

How are the tiles in WORDAMENT organized?

I'm trying to create a word game, just like WORDAMENT, in my spare time. In order to present a new round, I need to create a board with 16 letters organized in a 4*4 grid. Currently, I'm generating ...
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0answers
80 views

Algorithm : What is the scenario depicted in the below problem and how can it be solved?

Consider the following input: “4 2 1 4 2”. The first friend to arrive brings a box of length ‘4 cm’. height is same for all boxes. The second to arrive brings a box of length ‘2 cm’ and so ...
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3answers
3k views

Efficient algorithm to count number of substrings divisible by 3

Given a string of decimal digits, I have to find the number of all substrings divisible by 3 in the range L to R [both inclusive], where L & R are index[1-based] of the specified string string ...
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1answer
85 views

Matrices calculations on partial shape matching

I'm working in a shape recognition project where it is supposed for me to develop an application that receives two images: an original one and a sketch made by a user. I am supposed to detect contours ...
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2answers
195 views

Big-O notation for other cases

I was just reading answers to a question Plain English explanation of Big O From that i came to know that Big-O notation is just an "upper bound" of the complexity of an algorithm? But can we apply ...
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2answers
177 views

Finding common prefixes for a set of strings

I am trying to find common prefixes for a sorted set of strings. i.e. if the following strings are given: AB123456 AB123457 ABCDEFGH ABCDEFGX1 ABCDEFGY XXXX then my function should return three ...
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344 views

What is the simplest and universal algorithm for parsing C++ code? [closed]

I need to do some project specific automatic checking of source codes written in C++ Limitations: Algorithm and its implementation should be simple, easily maintainable, extendable and ...
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3answers
802 views

Algorithm which suggests synonyms based on some term?

Is there an algorithm which I can use in order to generate synonyms for some term (word) in respect of a spam. I am writing a simple spam filter. For example, I set that the app must omit a word ...
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3answers
925 views

Please explain the statement that the function an+b belongs to O(n^2) and Θ(n)?

Let's say I have a linear function f(n)= an+b, what is the best way to prove that this function belongs to O(n2) and Θ(n)? I do not need mathematical rigor here. I need a programmers answer. Some ...
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1answer
89 views

Algorithm to find the closest summation of elements in a list to a given number [duplicate]

Say I have a list {1,3,7,2,11,8,2} and I want to take x elements from the list and get the value 15.5. Is there an algorithm that would give me x elements in a list that, when added together, get ...