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

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3
votes
2answers
433 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
262 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
2answers
553 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 ...
2
votes
2answers
393 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 ...
1
vote
1answer
38 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 ...
12
votes
2answers
2k 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 ...
4
votes
2answers
556 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 ...
-2
votes
1answer
345 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 ...
1
vote
2answers
236 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 ...
2
votes
6answers
2k 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 ...
1
vote
3answers
306 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
584 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 ...
2
votes
5answers
494 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.
0
votes
0answers
56 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
2k 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 ...
4
votes
2answers
2k 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
289 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
1answer
126 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 ...
-2
votes
1answer
75 views

How to maintain trade off between number of columns in table vs join operations? [closed]

I have learnt that if there are more columns in table, then get those results using join query. How to decide the max number of columns in table? How feasible is "Join Operation" if too many table ...
1
vote
2answers
526 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 ...
0
votes
2answers
426 views

Data structures VS Classes and what happens if they merge? [closed]

Alright so I've learned this: Classes have public methods that perform operations on the class's data and they hide away their implementations. Data structures on the other hand, completely expose ...
0
votes
2answers
287 views

Most efficient data structure for implementing inheritance structure without classes

I have a number of types that all relate to each other in terms of them being 'derived' from one another. I'd need a way to do is relationships, which made me initially think of classes, but I ...
0
votes
1answer
63 views

Testing the Consumers of Subclassed Data Structures

PHP's SplQueue does not include a clear() or reset() function to wipe data out of the data structure. My application requires that functionality. This leaves two options: A) Create a subclass of ...
3
votes
4answers
356 views

fast n-gram access data structure

TL;DR Is there a data structure that'd quickly let me match words at any point (e.g., 'foo' matches 'foobar' and 'zoofoo'), and, ideally, returns a list of "characters that show up after the needle" ...
1
vote
1answer
217 views

Chained ruleset parsing and evaluation code: recommendations?

So I have to write a filtering system, which may apply preprocessed ruleset to data - and trigger some actions defined in the ruleset while continuing its evaluation. <ruleset name="1"> ...
0
votes
1answer
76 views

What is the difference between a Splay Tree and an Optimal Binary Search Tree?

Both these trees try to keep the most frequently accessed element at the top. Is there any difference between these two trees?
1
vote
2answers
174 views

Minimize touching the already-working code when a radical change is required

I have a code that highly relies on an Array structure like the following: $array['customer'][$customer_id]['details'][..]; // it goes to about 10 levels deep However, after almost two years ...
0
votes
1answer
76 views

Method to store some site content data, allowing reusability

(Don't believe this is a "best practice" question as I believe there will be a single better choice). I need to choose a data storage option to store specific site data to allow easy management and ...
4
votes
1answer
230 views

Designing storage service data structure for decoupled models sharing same data

Surely most of you remember the Norton Commander application where similar (sometimes the same) data is displayed in separate decoupled views. I'm building a web application that follows the same ...
17
votes
3answers
2k views

How do purely functional programming languages deal with fast changing data?

What data structures can you use so you can get O(1) removal and replacement? Or how can you avoid situations when you need said structures?
1
vote
3answers
350 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 ...
1
vote
2answers
273 views

Data retrieval and indexing

I have around 800,000 rows of data stored in the boost shared memory from the database. The data are in the form: Id Color Length Size 1 1 2 ...
2
votes
1answer
234 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 ...
0
votes
1answer
333 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 ...
2
votes
1answer
172 views

How to organize points on a sphere in bins and navigate between bins?

I'm having trouble coming up with a suitable way to navigate through a set of star coordinates in the Equatorial Coordinate System. My goal is to display those which are within a given range of ...
1
vote
1answer
313 views

Is there already a “Binder” data-structure?

I was thinking of a data structure that I cannot describe better than with the word "book", or more exactly "binder". I was wondering if this had already been implemented in libraries like Boost or ...
1
vote
1answer
113 views

Implementation/Representation of Symmetries in Chessboards

In a 8X8 chessboard, I was wondering how to implement the symmetry of the board. A lot of positions are just mirrors or rotations of one another (with no pawns or castling capabilities left the ...
1
vote
2answers
189 views

Documenting/defining data structures in Python

What is the preferred way to document the contents of and logic behind dynamically generated data structures in Python? E.g. a dict which contains the mapping of a string to a list of lists of ...
2
votes
2answers
169 views

Replacing static classes with global state to a series of POJOs, beginning to feel like an anti-pattern

I'm trying to refactor some code, and one of the major changes is to remove the (ab)use of static classes to give global state. I've tried to split up some of the 'global state' functionality with ...
5
votes
1answer
137 views

Bloom filters or similar, but with no false positive

To improve some lookups, I am considering the use of Bloom Filters. But in my use-case, the most probable outcome is that the element do exists in the target set. Bloom filters can have false ...
1
vote
0answers
48 views

Compound container for storing output from a parser

Consider a hierarchical structure like this directory [ [item_0;item_1;...;item_n] [item_0;item_1;inner_directory[...];item_m] other_directory [...] ] ...
4
votes
3answers
610 views

Is a tree with nodes that have reference to parent still a tree?

If we make reference to the parent for each node in a tree, do we still have a tree (by definition) anymore? Wikipedia definition is: In computer science, a tree is a widely used abstract data ...
4
votes
5answers
479 views

Is my understanding of abstract datatypes correct?

After reading lots of pages on various sites, I came to the conclusion that abstract datatype helps to separate the use of datastructure from its implementation. We can easily map the data into a ...
0
votes
2answers
260 views

Critique the Structure of my Horse Racing Betting Platform

I am creating a program (mostly just for fun) that displays live prices for horse racing markets and the prices that several models predict they should be. I am very interested in the optimal way to ...
0
votes
0answers
43 views

Designing online exam [duplicate]

I need to design an online exam server for an exam like GRE in which question difficulty increases if you answer correctly and decreases if you answer wrong. Questions are multiple choice ...
0
votes
1answer
243 views

Designing online exam

I need to design an online exam server for an exam like GRE in which question difficulty increases if you answer correctly and decreases if you answer wrong. Questions are multiple choice ...
0
votes
1answer
284 views

Is there any practical algorithm / data-structure that can't be done with non-recursive Lambda Calculus augmented with foldl?

In my search for a practical non-turing complete programming language, I've been paying attention to lambda-calculus with disallowed self-application - that is, x x forbidden. After taking that ...
2
votes
3answers
258 views

Why it is `(cons 1 (cons 2 (cons 3 nil)))` and not `(cons 3 (cons 2 (cons 1 nil)))` for [1,2,3]?

Is there any special reason that to construct list in Scheme you use (cons 1 (cons 2 (cons 3 nil))) instead of (cons 3 (cons 2 (cons 1 nil))) ? While the first seems more obvious because it ...
4
votes
2answers
414 views

Is there any particular reason for the use of lists over queues in functional programming languages?

Most functional programming languages such as Scheme and Haskell use lists as their main data structure. Queues are identical to lists, except for the fact appending to the end - not to the begin - ...
1
vote
2answers
174 views

Random access (read/write) in datastructures

Certain datastructures, like Python's Dictionary, are unordered/random read/written. As programming in python is iterative (and programming in general is?), how do these unordered datastructures ...