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

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1
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0answers
21 views

Cache-conscious data structure that does not require hashing

I am looking for a cache conscious data structure that does not require hashing. This is to avoid HashDoS without needing to use cryptographic PRFs such as SipHash, which are slow (~1 cycle/byte) ...
4
votes
2answers
71 views

Database design, processor vs inconsistency

I was wondering, if I have a table that stores, lets say, a user's transactions, then when I need to fetch the user's current balance I would have to go and use SUM() like SELECT SUM(value) FROM ...
1
vote
1answer
110 views

Does algorithm time complexity O(5) considered as O(1)? [duplicate]

I have someone homework to make and in the instructions it says that we need to implement a function in O(1). Now, does it mean that I can make my function in O(5) or O(2) or whatever?
7
votes
2answers
123 views

How to best design a job queue with constraints?

Consider the following situation: You have a program which creates numerous 'jobs' that need to be processed and places them into a queue. You have other worker programs which grab the next 'job' in ...
0
votes
2answers
76 views

JSON or XML or other - most time efficient for largely “read” of structured data

Considering that using a relational DB or other hierarchical or such databases is not an option, looking for the alternative approach using a simple (but very fast, efficient, distributed KV-store). ...
3
votes
1answer
191 views

How to pass data to OOP objects?

I'm new to this whole thing, so please tell me if I'm doing this wrong of if there's a better spot for my question. I'm making a game with basic systems for projectiles, npcs and items. This game ...
-1
votes
1answer
71 views

Data structure for storing sorted data

What's a good way to store loads of sorted string on a file so that inserts and reads are fast? I could store it up in a tree, and read/modify/store it as needed, but that seems wasteful for ...
4
votes
1answer
123 views

Word ladder efficency problem

I have a problem dealing with word ladders. The problem is: given two words and a dictionary file, find the shortest word ladder between the two words. So if given the words cat and pot: cat -> ...
4
votes
0answers
63 views

Modelling a complex schedule of work

I've got a real-world problem that I'm trying to represent and automate. I've simplified and abstracted it down to the following: There are n places of work (P1, P2, ..., Pn). Each place, Pn has a ...
16
votes
6answers
40k 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
150 views

How to design an iterable but immutable (read-only) collection

My program models a sport tournament which has one or many events or categories. The class Event has members like players or courts as a List, as well as some dictionaries using the class Map. So far ...
1
vote
1answer
64 views

Joining binary trees

Suppose we have a set of binary trees with their inorder and preorder traversals given and where no tree is a subtree of another tree in the given set. Now another binary tree Q is given. Find ...
2
votes
2answers
195 views

Is it a bad practice to use JSON strings as keys of objects?

On languages such as Haskell, most datatypes have instances which allow their values to be used as keys of structures such as Maps. JavaScript has reasonably fast maps, there called objects, but those ...
3
votes
3answers
345 views

How can I represent a flowchart, complete with conditional logic using JSON or XML?

One part of a project I'm working on is interactive scripts for call centre staff. Pretty much every possibility I can think of in this case can be represented on paper as a flowchart, which is why ...
2
votes
1answer
65 views

Caching in '3D' - data-structures and octree recursion - hrrm!

The Situation: I have 68GB of data that is conceptually realized as a 3D matrix of 8-bit values with dimension 4096*4096*4096. I need to access multiple sections of this data for processing in a ...
-5
votes
0answers
22 views

I have 3 groups of constant values where I need to return the group name if my search element matches with any of the element in group

I have 3 groups like: days = {Sat, Sun, Mon}; weeks = {1, 2, 3, 4}; months = {Aug, Sep, Dec}; I have an element Sun, if this element matches with any of group, in this case it is Sunday, so return ...
1
vote
2answers
206 views

What is the best data structure to store 2 keys and 3 values?

Well, I am having two keys and 3 values for that. Say key1,key2,value1,value2,value3. In future may the values can be increased like value4, value5 so on. I need to get the ...
0
votes
1answer
62 views

Datagrids vs Databases - what are the differences?

There are some datagrids I had quick look into: Angular UI Grid ag-Grid, one more link Kendo UI Grid Also, previously I had a very small experience with MySQL. What are the differences between ...
2
votes
2answers
71 views

Algorithm for implementing QOS in my proxy

Here's the situation: I'm making a proxy (for the moment running on my laptop) which deals with HTTP(S) requests from incoming clients (for the moment only one client, i.e. my Chrome browser on my ...
0
votes
1answer
84 views

Data Structure for Form or Survey [closed]

I am planning an app which allows users to complete surveys/forms. I'm having trouble planning the data schema for the forms. I really want to have a data structure which can be mostly automatically ...
0
votes
1answer
17 views

What relationship describes two different abstractions of the same dataset

I am wondering if there is a specific term for when multiple representations are data equivalent. Meaning that you can transfer the data from one representation to the other without any loss of data. ...
2
votes
1answer
52 views

Matrix multiplication range queries

I have a huge list of matrix i.e A = {M0, M1, M2 .. Mn}. I have a task to find the product of all the matrices in a given range {x,y} i.e Mx * Mx+1 * Mx+2 ... * My. I would like to know if there is ...
1
vote
2answers
64 views

What design patterns exist for large dataset manipulation within MVC for a rich client data grid?

I want to feed an HTML5 data grid with large data sets that the client will want to manipulate in different ways, e.g. aggregation, grouping, pivoting. The data comes from different web services and ...
0
votes
0answers
14 views

PHP array implementation what hashtable's 'bool persistent' does stand for? [migrated]

I read So let’s just say that persistent specifies that the hash table can live between multiple requests. In Nikic's blog about PHP array implementation There is no further information in ...
-2
votes
4answers
59 views

How can I represent a multi-dimensional grid? [closed]

I'm trying to find an efficient way to represent a grid in any number of dimensions. I would want to be able to specify a set of coordinates and then get the value stored in the location on the grid. ...
5
votes
1answer
85 views

How does cuckoo hashing guarantee O(1) lookups in presence of persistent hash collisions

Most hash table implementations guarantee O(1) average case but O(n) maximum case for lookup (where 'n' is the number of keys in the table). But Cuckoo Hashing is described as O(1) maximum. ...
-2
votes
0answers
40 views

Caching results by serialized form fields

I have a remote data source ("The remote database") I have a local MySQL database ("The local database") I have a HTML form which queries the remote database ("The form") When the form is submitted, ...
-3
votes
2answers
58 views

class name for linked lists

I have a question about how to name a class in java. Could a class name be arbitrary or have to obey some rules? For example, I want to define linked lists in a class, does the class name have to be ...
1
vote
1answer
29 views

File structure for storing pixels that changed from one image to another

Have two images with the same dimensions. I want to create a file that contains information on what pixels are different between the two images. The file should also tell me the value of the new ...
8
votes
2answers
261 views

How to handle complex calculated fields in an ORM

In our API we've got a few central datatypes which need to be "decorated" (so to speak) after retrieval from the database with calculated values. The database is accessed through an ORM which follows ...
1
vote
0answers
80 views

How to structure enum data to achieve the desired effect

I'm making a framework for building simple html websites for an embedded system and I want to make it bulletproof in a way that a user can't make mistakes in building the html document. As I've ...
54
votes
4answers
13k views

Which algorithms/data structures should I “recognize” and know by name? [closed]

I'd like to consider myself a fairly experienced programmer. I've been programming for over 5 years now. My weak point though is terminology. I'm self-taught, so while I know how to program, I don't ...
4
votes
2answers
163 views

Can StringBuilder be used to effectively store and manage multiple variables of data?

Using C# I want to create one or more text files to store all the data pertaining to a particular 'Thing' on the same line. I am presently leaning towards StringBuilder as per the following. ...
1
vote
1answer
58 views

How many vertices/nodes are too many in a graph and stop being beneficial?

Background I'm working on a project that requires me to keep track of transactions as well as the flow of items in a game. In order to do that, I'm storing those transaction in a graph db ...
21
votes
3answers
13k views

How exactly is an Abstract Syntax Tree created?

I think I understand the goal of an AST, and I've built a couple of tree structures before, but never an AST. I'm mostly confused because the nodes are text and not number, so I can't think of a nice ...
5
votes
1answer
345 views

Efficient data structure to implement fake file system

I want to implement a data structure that will hold the paths of directories, sort of fake file system. Input:- I have a text configuration file containing the paths as follows ... C:/temp1 ...
2
votes
1answer
144 views

Standard System that connects to any datasource without much/any source-specific code?

We are a small team doing work on a LoB system that needs to connect to varied systems such as ERPs and CRMs to extract business processes like invoices, customer info, production orders and the such, ...
2
votes
2answers
154 views

C++ object references vs. lookup

Let's assume there are 2 classes: Country and City. Both of them have names, so a map would suit as conainer map<std::string, Country> countries; In the country class there is a similar map ...
2
votes
1answer
94 views

What method for storing a text file in memory (c not c++) would allow me to open any format(UTF-8, Binary, etc) and a file of any size?

My first thought here is to use a dynamic array, but I am looking for something better. Currently I have the text files open into "chunks". Every word or group of spaces makes up a "chunk". Then I ...
1
vote
0answers
23 views

Pagination with multiple groupings

I have a data model that looks like this: Group 1 --Sub group1 ----item1 ----item2 ----item3 --Sub group2 ----item1 ----item2 ----item3 Group 2 --Sub group1 ----item1 ----item2 ----item3 --Sub ...
3
votes
1answer
91 views

PHP OOP, structuring my objects properly

I have an architecture similar to this: User (Name, Email, ID...) ---- Studios (Name, Location, Description...) ---------- Videos (Title, Description, URL, Length, Views...) Simply put, a user can ...
0
votes
2answers
49 views

How to model a property with two different formats and ranges

I am designing a JSON based data schema to describe the visual appearance of blocks similar to HTML elements. It should feel familiar for somebody knowledgable in HTML/CSS but is more restrictive due ...
3
votes
1answer
335 views

What do banks actually use as a data type for money? [closed]

I'm aware of a few good options: Big integers (e.g., int64_t, mpz_t, any bignum lib) to represent cents or 10-n cents—say, an integer represents 1/100 of a penny ($1.05 == 10500). This is called a ...
13
votes
9answers
5k views

Data structure for accessing units of measure

TL;DR - I'm trying to design an optimal data structure to define units within a unit of measure. A Unit of measure is essentially a value (or quantity) associated with a unit. SI Units have seven ...
10
votes
1answer
385 views

How does a skip list work?

For a homework assignment, I need to understand how a skip list works. I've been programming for a little over 2 years now (I know that's not that long in reality), and I have never even heard of a ...
3
votes
2answers
210 views

Can a tree be used to create a stack?

I'm aware that linked lists, sets and arrays can be used to create stacks by themselves. The theory behind it is this linked-list: In some languages, a linked-list is substitutable for an array. ...
-2
votes
1answer
49 views

Considerations when making data structure and algorithm choices [closed]

What are some reasons you may choose a worse runtime algorithm? And what are some advantages of a linked list vs a hash table/array where access is constant time.
4
votes
1answer
179 views

Detecting surface faces of a huge 3D mesh/grid

I've written a module in my application that creates a mesh from existing coordinate and face data. The number of vertices in the mesh could easily exceed 10 million and the same goes for the faces. ...
2
votes
4answers
225 views

Best data structure for representing English verb forms

I need to come up with a data structure to keep information about English verb forms. In most cases a verb can be in one of 4 forms: base, present participle, past participle and past simple, for ...
34
votes
8answers
14k 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 ...