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

learn more… | top users | synonyms

2
votes
1answer
62 views

How can a true Vector be implemented in Haskell?

How could a true Vector type be implemented in Haskell? In order for something to be a Vector, it has to be stored sequentially in memory, with O(1) random access. But Haskell hides its memory ...
1
vote
1answer
154 views

Graph data structures and journal format for mini-IDE

Background: I am writing a small/partial IDE. Code is internally converted/parsed into a graph data structure (for fast navigation, syntax-check etc). Functionality to undo/redo (also between ...
1
vote
0answers
38 views

Managing debug information of C program for Eclipse

I am not sure if the title is appropriate. I have written a parser for CDB files in C# and ANTLR that creates runtime objects for me such that I can pass it to the TCF Agent which takes care of ...
5
votes
0answers
62 views

Are “skip deltas” unique to svn?

The good folks who created the SVN version control system use a structure they refer to as "skip deltas" to store the revision history of files internally. A revision is stored as a delta against an ...
0
votes
2answers
126 views

How to present a stable data model in a public API that allows internal data structures to be changed without breaking the public view of the data?

I am in the process of developing an application that allows users to write C# scripts. These scripts allow users to call selected methods and to access and manipulate data in a document. This works ...
0
votes
1answer
179 views

Find possible variations of one item out of multiple baskets.

I have three baskets of balls and each of them has 10 balls which have the following numbers: Basket 1: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 Basket 2: 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 ...
3
votes
3answers
190 views

Data Oriented Design - impractical with more than 1-2 structure “members”?

The usual example of Data Oriented Design is with the Ball structure: struct Ball { float Radius; float XYZ[3]; }; and then they make some algorithm that iterates a std::vector<Ball> ...
10
votes
2answers
479 views

In-memory datastore in Haskell

I want to implement an in-memory datastore for a web service in Haskell. I want to run transactions in the STM monad. When I google hash table steam Haskell I only get this: Data. BTree. HashTable. ...
2
votes
0answers
111 views

Is using MultiMaps code smell? If so what alternative data structures fit my needs?

I'm trying to model nWoD characters for a roleplaying game in a character builder program. The crux is I want to support saving too and loading from yaml documents. One aspect of the character's is ...
1
vote
2answers
164 views

Best way of storing a small number of user credentials

I'm working on a messaging application, based on a server/client architecture. Now I am thinking about the way how to store the user credentials. It's not a huge number, just about 20 entries with ...
2
votes
3answers
120 views

Most efficient way to store this collection of moduli and remainders?

I have a huge collection of different moduli and associated with each modulus a fairly large list of remainders. I want to store these values so that I can efficiently determine whether an integer is ...
2
votes
2answers
58 views

Quadtree with duplicates

I'm implementing a quadtree. For those who don't know this data strucutre, I am including the following small description: A Quadtree is a data structure and is in the Euclidean plane what an ...
0
votes
2answers
72 views

Tournament bracket method to put distance between teammates

I am using a proper binary tree to simulate a tournament bracket. It's preferred any competitors in the bracket that are teammates don't meet each other until the later rounds. What is an efficient ...
0
votes
2answers
89 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 ...
10
votes
4answers
4k views

EAV - is it really bad in all scenarios?

I'm thinking to use EAV for some of the stuff in one of the projects, but all questions about it in stackoverflow end up to answers calling EAV an anti pattern. But I'm wondering, if is it that wrong ...
8
votes
5answers
9k views

How to quickly search through a very large list of strings / records on a database

I have the following problem: I have a database containing more than 2 million records. Each record has a string field X and I want to display a list of records for which field X contains a certain ...
4
votes
2answers
222 views

Overriding GetHashCode in a mutable struct - What NOT to do?

I am using the XNA Framework to make a learning project. It has a Point struct which exposes an X and Y value; for the purpose of optimization, it breaks the rules for proper struct design, since its ...
0
votes
1answer
276 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 ...
22
votes
2answers
737 views

Is there a data structure for this type of list/map?

Perhaps there's a name for what I want, but I'm not aware of it. I need something similar to a LinkedHashMap in Java, but where it returns the 'previous' value if there's no value at the specified ...
1
vote
4answers
644 views

Data structure for file search

I've asked this question before and I got a few answers/idea, but I'm not sure how to implement them. I'm building a telecom messaging solution. Currently, I'm using a database to save my ...
3
votes
2answers
180 views

Data structure for grid with negative indeces

Sorry if this is an insultingly obvious concept, but it's something I haven't done before and I've been unable to find any material discussing the best way to approach it. I'm wondering what's the ...
2
votes
1answer
106 views

Where to implement thread-safety logic for my queue data structure?

I will immediately confess that I do very little multithreading, so questions of style and organization in this domain a little fresh to me. I've written a data structure (in Python, if that matters) ...
0
votes
1answer
105 views

Exercise 3.6: Skiena Algorithm Design Manual

I am preparing for interview and try to solve the exercise problems of the book. 3-6. [5] Describe how to modify any balanced tree data structure such that search, insert, delete, minimum, and ...
9
votes
2answers
685 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 ...
1
vote
1answer
36 views

Benefits of caching the count of items in a data structure versus on-demand calculation?

Given a data structure, I want to provide an API method Size which returns the number of items. I am vacillating between 2 approaches: Maintain a count and increment/decrement it in response to ...
9
votes
2answers
996 views

What is the relationship between data structures and algorithms? [closed]

I have been searching for a good online course in data structures but have found that Google also returns results for algorithms courses, which say stuff like: In this course you will learn ...
6
votes
1answer
408 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 ...
1
vote
3answers
288 views

Choice between 1-dimensional and 2-dimensional array

I'm implementing the Chessboard class to represent the chessboard. I've to implement the transformations (reflections and rotations) on the chess board possible. The possible transformations includes ...
-3
votes
1answer
153 views

Does implementing algorithms improve your programming skills? [duplicate]

I have been self studying algorithms and data structures for some time now and currently enjoying it. Whenever I understand an algorithm, I usually try to code them from scratch for fun and I always ...
0
votes
1answer
219 views

How does Google store its PageRank matrix?

I'm curious to know how Google stores the matrix that's used in the PageRank algorithm; and am looking for a data-structure for storing a very-large (not fitting in memory of any one computer) sparse ...
1
vote
2answers
1k views

Equivalent of #map in ruby in golang

I'm playing with Go and run into something I'm unable to find in Google, although there is certainly something that exists: I'm using the following struct: type Syntax struct { name string ...
2
votes
6answers
1k views

How did programmers implement Linked list ideas before the object oriented paradigm?

Linked lists, as far as I have seen, are largely implemented using object-oriented ideas. (having an object that holds some information and the address of the next link). How were Linked-lists ...
0
votes
1answer
100 views

Traversing an AST using Visitors

I'm writing a compiler for a C-like language, and I'm looking for an elegant way to traverse my abstract syntax tree. I'm trying to implement the Visitor pattern, although I'm not convinced that I'm ...
8
votes
13answers
6k views

What are some good, simple examples for queues?

I'm teaching CS2 (Java and data structures), and am having some difficulty coming up with good examples to use when teaching queues. The two major applications I use them for are multithreaded message ...
1
vote
3answers
207 views

what is the javascript internal data structure?

Consider a basic js object: var obj={x:1,y:'2'}; Is this stored internally as a hashtable or does js use a different mechanism for key value pairs? If they are hash tables does anyone know how they ...
0
votes
1answer
81 views

What happens to equal elements when inserting into a binary search tree?

Most BST examples show a sample of a BST with unique values; mainly to demonstrate the order of values. e.g. values in the left subtree are smaller than the root, and values in the right subtree are ...
5
votes
6answers
2k views

Why is the usage of string keys generally considered to be a bad idea?

This has been bugging me for a while. Most of the time, when it comes to storing data in structures such as hashtables, programmers, books and articles insist that indexing elements in said structures ...
21
votes
7answers
3k views

Should I keep investing into data structures and algorithms?

These days, I'm investing heavily in data structures and algorithms and trying to solve some programming puzzles. I'm trying to code and solve with Java and Clojure. Am I wasting my time? should I ...
5
votes
7answers
924 views

Priority list of tasks stored in a database

I am trying to think of the best way to do the following: I have a list of tasks stored in the database. A task has a priority assigned to it. You can change the priority of a task to reorder the ...
2
votes
5answers
363 views

how to design a stack without using java library or using list [closed]

I have a question how to design a stack without using list or array? This is one question that I want to think about as I want to better understand stack.
7
votes
8answers
9k views

What is the difference between an Array and a Stack?

According to Wikipedia, a stack: is a last in, first out (LIFO) abstract data type and linear data structure. While an array: is a data structure consisting of a collection of elements ...
0
votes
0answers
44 views

streaming data in memory aggregation

We have a stream of data we're aggregating stats over and putting into a python dictionary (sent from kafka). Every X time interval, We update our database with these aggregated metrics. This ...
0
votes
0answers
50 views

How to store progress of abstract events?

I making a game in node.js. I have players and they can perform a lot of actions. Actions are all coded as functions, and they change certain variables in either User object or other objects that ...
0
votes
1answer
355 views

Is a PHP array an example of a dynamic data structure?

I did my homework, and it says that dynamic data structures are "data structures that change in size as a program needs it to by allocating and de-allocating memory from the heap". So I was ...
1
vote
2answers
291 views

Why does Python use hash table to implement dict, but not Red-Black Tree? [closed]

Why does Python use hash table to implement dict, but not Red-Black Tree? What is the key? Performance?
2
votes
2answers
110 views

Collection vs data structure vs aggregate

I know three terms that have to do with storing objects or data. I'm not sure I understand the exact differences between the terms. Please confirm if what I'm about to write is accurate. A data ...
0
votes
0answers
38 views

What is a good way to store geographical data for distance calculations

What would be the best way to store data in a database for geographical calculations? Say I have an ItemsForSale table paired to a Users table which holds their geo location. I know I can use latitude ...
0
votes
0answers
8 views

Globalizing geographical information in data design

I am building my database/models/viewmodels right now and can't think of a good variable name to define for the equivalent of a "state" in other countries. I currently have Country and City which are ...
8
votes
5answers
4k views

Real world usage of DelayQueue

What would be a real world usage of DelayQueue, what common problem it was designed to solve?
1
vote
0answers
93 views

What is the underlying mechanism behind va_list and where is it defined?

http://www.cplusplus.com/reference/cstdarg/va_list/ According to the above link, va_list is an argument or parameter used in some macros - va_start, va_arg, va_end. These macros are present in the ...