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

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0
votes
1answer
609 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
5k 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 ...
23
votes
7answers
4k 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
1k 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
503 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
14k 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
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 ...
5
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
305 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 ...
10
votes
5answers
6k views

Real world usage of DelayQueue

What would be a real world usage of DelayQueue, what common problem it was designed to solve?
-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 ...
0
votes
2answers
437 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 ...
1
vote
2answers
1k views

Radix exchange sort implementation?

I need a little help understanding the implementation of radix exchange sort algorithm. Radix exchange (I don't know if it's the exact name in english based literature) is a lot similar to quicksort, ...
6
votes
3answers
967 views

Faster reads, on an infinite grid plane, than using a hash table?

In the past, I've had alot of success just using a .NET Dictionary, with a TKey consisting of the X,Y coordinates merged together. However its read performance, despite being amortized constant time, ...
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 ...
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"> ...
41
votes
6answers
4k views

How necessary is it to follow defensive programming practices for code that will never be made publicly available?

I'm writing a Java implementation of a card game, so I created a special type of Collection I'm calling a Zone. All modification methods of Java's Collection are unsupported, but there's a method in ...
0
votes
2answers
289 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 ...
3
votes
4answers
360 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" ...
4
votes
1answer
231 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 ...
0
votes
1answer
79 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 ...
3
votes
1answer
330 views

How do I transparently cache data in intermediate stages of processing?

I am working with MATLAB on a model reduction algorithm. It is basically a data processing pipeline. ckt = generate_ckt(ckt_properties); freq = generate_fpoints(fconfig); result = ...
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?
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 ...
1
vote
2answers
278 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 ...
0
votes
2answers
251 views

Data structure theory based on graph rewriting [closed]

First of all, I'm looking for a book, publication, project or any kind of information that should probably exceed the limits normally imposed on answers in this kind of forum. I know the rules about ...
4
votes
5answers
485 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 ...
1
vote
1answer
314 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
2answers
521 views

Arrow => in Perl

What does the => mean in Perl? my $CreateArray = [ objectClass => [ "top", "person", "organizationalPerson", "inetOrgPerson" ], cn => "Jane User", uid => "0000001", sn => "User", mail ...
1
vote
1answer
387 views

Handling timeout in network application

How can I handle timeouts in a network application. I'm implementing a provisioning system on a Linux server, the code is huge so I'm going to put the algorithm, it works as like this Read ...
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
190 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 ...
0
votes
3answers
990 views

Collection providing lookup by one of several keys [closed]

What do you call a collection in which each item may be looked up by one of multiple keys? A partial, simplified definition in C# might be: class MyDataStructure<TKey1, TKey2, TValue> { ...
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 ...
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 - ...
4
votes
2answers
933 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 ...
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 [...] ] ...
0
votes
2answers
261 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
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 ...
1
vote
3answers
383 views

What can Go chan do that a list cannot?

I want to know in which situation Go chan makes code much simpler than using list or queue or array that is usually available in all languages. As it was stated by Rob Pike in one of his speeches ...
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
244 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 ...
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 ...
1
vote
2answers
178 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 ...
1
vote
0answers
208 views

Most suitable data structure for in-memory string -> int conversion for variable length strings

My project involves validating and normalising email addresses in this format [userpart]@[domainpart].[tld] After syntactic validation of the address, [tld] is checked to exist, otherwise the ...
7
votes
4answers
889 views

How do we keep dependent data structures up to date?

Suppose you have a parse tree, an abstract syntax tree, and a control flow graph, each one logically derived from the one before. In principle it is easy to construct each graph given the parse tree, ...
0
votes
2answers
427 views

PHP SplFixedArray How To Deal With billions of indexes?

I've built a flatfile db system that will work like mini-noSQL system and it split db to smaller files, and I did a SplFixedArray wrapper for it with a method for searching usage built on preg_grep. ...