Questions regarding efficient storing and representing data within a software application.

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1
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1answer
215 views

Marked nodes in Fibonacci heaps

I don't understand why Fibonacci heaps have marked nodes (picture). A node is marked when its child is deleted. Quoting from Wikipedia: "[Keeping degree of each node low] is achieved by the rule that ...
2
votes
1answer
102 views

creating simple states for a stateless input

Given an input device (basically a keyboard) that reports keyup and keydown, how may I most efficiently store and retrieve information about which keys are currently depressed? My first thought was a ...
0
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2answers
193 views

Data structure for fast StartsWith filtering of a dictionary

I have a list of english words. I'm trying to come up with a data structure that allows me to do fast StartsWith filtering, like: var words = dictionary.StartsWith("foo"); I was thinking of ...
16
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2answers
1k views

What's the difference in content between Chris Okasaki's 1996 thesis and 1999 book, Purely Functional Data Structures?

I want to read Purely Functional Data Structures. I've easily found the thesis (which is freely available as a PDF), but see that there's a book available also. So I'd like to know what the ...
7
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4answers
7k views

What is the point of using lists over vectors, in C++?

I've run 3 different experiments involving C++ lists and vectors. Those with vectors proved more efficient, even when a lot of insertions in the middle were involved. Hence the question: in which ...
7
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2answers
1k views

Using a stream manipulator (endl) or a newline escape character (\n)?

I don't have a specific context in which I'm asking the question, but while I was reading a beginner book on C++ I noticed the use of both an endl stream manipulator and a newline escape character ...
0
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2answers
450 views

Algorithms for data structures in distributed system

The hash table data structure can be easily spread across multiple machines with a simple algorithm to distribute the keys: machine_to_query = item_key % machine_count When you want to read and ...
5
votes
1answer
754 views

How do scalable bloom filters work?

I was reading up on scalable bloom filters and could not understand how each time a constituent bloom filters fills up, a new bloom filter with larger size is added. The elements that contributed to ...
1
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2answers
3k views

How to increase the efficiency of an Immutable Queue in java?

I have been developing an Immutable queue in java, but the version I have developed is supposedly slow and I have been suggested to create a faster version of the same and I have no idea as to how to ...
2
votes
2answers
634 views

Thoughts on a custom data structure for a node/chain implementation

I am designing a simple GUI that will allow a user to create a GPX route by clicking repeatedly on a map panel. I am faced with a design dilemma for how to represent the nodes and route. This ...
4
votes
2answers
726 views

Creating huge decision tree

I'm to write an event correlator. A fundamental part of the system will be a decision tree that recognizes the origin of the fault basing on recorded states and log files. Often many accidents will ...
3
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6answers
445 views

Should a database table(s) structure match its intended data structure(s) in the logic?

This question branches out of this question, What are the differences between algorithms using data structures and algorithms using databases?. The General Question Should a database table(s) ...
6
votes
4answers
316 views

Representing a rule in a ruleset

How to represent rules for a rule engine as objects? A rule would be if (booleanExpression(input)) then a chain of generic actions" else next rule ...where the generic actions might be e.g. ...
7
votes
4answers
2k views

What are the differences between algorithms using data structures and algorithms using databases?

The General Question What are the differences between algorithms using data structures and algorithms using databases? Some Context This is a question that has been bugging me for some time, and I ...
1
vote
3answers
699 views

What data structure could a word processor use to map the user's caret position/text selection to its internal representation of the document?

Word processors (e.g. Microsoft Word) display documents to the user as styled text. The user can select a part of this text and apply styles to it, and edit the text. The word processor must (I ...
3
votes
1answer
114 views

Representing domain objects

This is related to my recent question regarding naming awkward domain objects. A number of answers indicated I was using the wrong representation for the domain objects. To summarize, I chose to use ...
-1
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1answer
587 views

Simple dependency tree diagram generator [closed]

I have a need to produce a simple dependency tree diagram. The input data would be in the following simple format: ITEM_NAME DEPENDENCY ---------------------------- ITEM_101 ITEM_75 ITEM_102 ...
3
votes
2answers
2k views

How, when, and why do developers use custom data structures in python?

Python's lack of pointers makes data-structure construction intuitively more challenging, and has so much built in functionality that, as an amateur, I can't see when, why, or how you would create ...
20
votes
3answers
758 views

How do I express subtle relationships in my data?

"A" is related to "B" and "C". How do I show that "B" and "C" might, by this context, be related as well? Example: Here are a few headlines about a recent Broadway play: David Mamet's Glengarry ...
4
votes
3answers
656 views

Is it conceivable to have millions of lists of data in memory in Python?

I have over the last 30 days been developing a Python application that utilizes a MySQL database of information (specifically about Norwegian addresses) to perform address validation and correction. ...
11
votes
1answer
8k views

Sets Data Structure in Golang

I really like google golang but could some one explain what the rationale is for the implementors having left out a basic data structure such as sets from the standard library?
-3
votes
1answer
612 views

map data structure in pacman [closed]

I am trying to make a pacman game in c#. I have done some basic work and have previously replicated games like copter-it and minesweeper. I am confused about how to implement the map in pacman. Which ...
5
votes
3answers
330 views

Generating Deep Arrays: Shallow to Deep, Deep to Shallow or Bad idea?

I'm working on an array structure that will be used as the data source for a report template in a web app. The data comes from relatively complex SQL queries that return one or many rows as one ...
4
votes
2answers
729 views

Which design better when use foreign key instead of a string to store a list of id

I'm building online examination system. I have designed to table, Question and GeneralExam. The table GeneralExam contains info about the exam like name, description, duration,... Now I would like to ...
4
votes
2answers
391 views

Fast set indexing data structure for superset retrieval

I am given a set of sets: {{a,b}, {a,b,c}, {a,c}, {a,c,f}} I would like to have a data structure to index those sets such that the following "lookup" is executed fast: find all supersets of a given ...
5
votes
2answers
960 views

Data structure for pattern matching

Let's say you have an input file with many entries like these: date, ticker, open, high, low, close, <and some other values> And you want to execute a pattern matching routine on the ...
0
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3answers
186 views

I need some help creating a non-binary tree (or some other data structure that will better solve my problem)

I have about ten lists of numbers and some strings. Each list has about <= 30K lines. Each line on a list has a distinct number. I need to build an efficient way of finding all the lines in each ...
4
votes
2answers
730 views

Patterns for a tree of persistent data with multiple storage options?

I have a real-world problem which I'll try to abstract into an illustrative example. So imagine I have data objects in a tree, where parent objects can access children, and children can access ...
30
votes
7answers
6k views

When to use DAG (Directed Acyclic Graph) in programming?

I recently found a framework named ecto. In this framework, a basic component named "plasm", which is the ecto Directed Acyclic Graph.In ecto, plasm can be operated by ecto scheduler. I am ...
6
votes
1answer
278 views

How to design data structures for sharding?

When designing data structures for an application, what are some best practices to make sure it can be sharded? In particular, which of the following is better: Creating relationships in databases ...
6
votes
1answer
1k views

What is the usage of Splay Trees in the real world?

I decided to learn about balanced search trees, so I picked 2-3-4 and splay trees. What are the examples of splay trees usage in the real world? In this Cornell: ...
3
votes
2answers
343 views

I have data that sends in “bursts” of 100 records with a significant delay. How do I structure my classes for multithreading?

My datasource sends information in 100 batches of 100 records with a delay of 1 to 3 seconds between batches. I would like to start processing data as soon as it's received, but I'm not sure how to ...
3
votes
1answer
768 views

How should I architect my Model and Data Access layer objects in my website?

I've been tasked with designing Data layer for a website at work, and I am very interested in architecture of code for the best flexibility, maintainability and readability. I am generally acutely ...
1
vote
2answers
506 views

Count function on tree structure (non-binary)

I am implementing a tree Data structure in c# based (largely on Dan Vanderboom's Generic implementation). I am now considering approach on handling a Count property which Dan does not implement. The ...
1
vote
6answers
4k views

Serializing Data Structures in C [closed]

I've recently read three separate books on algorithms and data structures, tcp/ip socket programming, and programming with memory. The book about memory briefly discussed the topic of serializing data ...
5
votes
2answers
244 views

Data structures for storing finger/stylus movements in drawing application?

I have a general question about creating a drawing application, the language could be C++ or ObjectiveC with OpenGL. I would like to hear what are the best methods and practices for storing strokes ...
2
votes
1answer
220 views

2D grid with multiple types of objects

This is my first post here in programmers.stackexchange (I'm a regular on SO). I hope this isn't too general. I'm trying a simple project to learn Java from something I've seen done in the past. ...
2
votes
1answer
155 views

Separating validation from persistence in models?

Models in an MVC application gets kind of hard to test when validation of data and persistence of data is baked together in the model. I would like to test those separately to prevent doing ...
3
votes
3answers
404 views

Internal Mutation of Persistent Data Structures

To clarify, when I mean use the terms persistent and immutable on a data structure, I mean that: The state of the data structure remains unchanged for its lifetime. It always holds the same data, ...
6
votes
1answer
153 views

Unit testing a text index

Consider a text index such as a suffix tree or a suffix array supporting Count queries (number of occurrences of a pattern) and Locate queries (the positions of all the occurrences of a pattern) over ...
5
votes
2answers
728 views

Efficient Data Structure for holding a graph

Problem Link - http://opc.iarcs.org.in/index.php/problems/NUMTRIPLE In my opinion, the problem can be solved by a data structure, that shows how each number is connected to another, and via recursion ...
3
votes
1answer
356 views

Amazon Kindle - Whispersync implementation?

For those who are not aware of Kindle's whispersync, here is how it works (from amazon.com): "...Whispersync synchronizes the bookmarks and furthest page read among devices registered to the same ...
0
votes
1answer
51 views

Create association between informations

I deployed a project some days ago that allow to extract some medical articles using the results of a questionnaire completed by a user. For instance, if I reply on questionnaire I'm affected by ...
1
vote
2answers
725 views

Does the Head(start) pointer of Doubly Linked list points previously to the tail(last) node

I have one question in my mind that in case of circular doubly linked list the head pointer of the doubly linked list also logically point to the next pointer of the tail node of the linked list and ...
2
votes
1answer
4k views

Most efficient Implementation a Tree in C++

I need to write a tree where each element may have any number of child elements, and because of this each branch of the tree may have any length. The tree is only going to receive elements at first ...
1
vote
2answers
5k views

Generic Adjacency List Graph implementation

I am trying to come up with a decent Adjacency List graph implementation so I can start tooling around with all kinds of graph problems and algorithms like traveling salesman and other problems... ...
3
votes
3answers
440 views

Data structure: sort and search effectively

I need to have a data structure with say 4 keys . I can sort on any of these keys. What data structure can I opt for? Sorting time should be very little. I thought of a tree, but it will be only help ...
6
votes
3answers
2k views

Data classes: getters and setters or different method design

I've been trying to design an interface for a data class I'm writing. This class stores styles for characters, for example whether the character is bold, italic or underlined. But also the font-size ...
9
votes
5answers
4k views

Configuration data: single-row table vs. name-value-pair table

Let's say you write an application that can be configured by the user. For storing this "configuration data" into a database, two patterns are commonly used. The single-row table CompanyName | ...
0
votes
5answers
970 views

Learning basic algorithms - better C or C++? [closed]

I'm studying fundamental algorithms (quicksort, mergesort, binary trees, etc..) and I'm going to re-code every algorithm by scratch to learn how they work. Should I code them in C or C++? I think with ...