Questions tagged [data-structures]
Questions regarding efficient storage and representation of data within a software application.
0
votes
1answer
120 views
Efficiency in Java: Object reference vs id reference
I have to represent a certain data structure, in which I have nodes that are related between them. Each node has its numeric id, and a list containing the next directly related nodes and another list ...
0
votes
0answers
20 views
How to combine multiple Tries for complex searching and filtering across tables?
Say I have a database with 100 tables. Scattered throughout the tables are some string columns for short things that could be considered usernames/tags/categories/hashtags/addresses/placenames/other ...
-3
votes
0answers
36 views
Problem in removing elements in priority queue in java
I'm removing nodes from priority queue on the base of fitness.Node with Lowest fitness will come out first. it is working alright e.g {3,1,2,4} it has 0 fitness,{2,3,3,3} it has 2 fitness value,{1,2,3,...
1
vote
1answer
17 views
Data Matching In VBA - Best way to deal with dynamic data and user entry?
Background
I am currently building this project with VBA, just to keep in the back of your mind when thinking about my question.
Imagine 2 adjacent blocks, in Excel. The first block is made up of ...
-6
votes
1answer
29 views
Give a list of a from area code and to area code and a distance between them,which data structure?
What data structure i can use to lookup given a fromCode and toCode apart from hashMap which results in more number of entries in the memory.
We are ok with log(n) efficiency also.
Example data:
...
2
votes
2answers
106 views
How to structure database for daily events?
I'm storing data which logs whether or not a user has logged their attendance for a given day. Some days are unimportant (holiday, weekend), so those are also stored.
The two requirements are that:
...
4
votes
2answers
231 views
Game Playing AI - Strategy to overcome the transposition table taking up too much memory?
I've made an engine that plays Connect Four using the standard search algorithms (minimax, alpha-beta pruning, iterative deepening, etc). I've implemented a transposition table so that the engine can ...
-1
votes
2answers
111 views
How to represent a directory structure in a binary tree?
I was just thinking about implementing a binary tree with its root pointing to the parent folder and then the children pointing to subdirs nested within to store a directory structure in a binary tree....
2
votes
1answer
91 views
Achievement System CRUD data structure
I'm developing this Achievement System and it must have a CRUD, that admins access to create new achievements and it's rules. I need some help with the Achievement CRUD data structure.
Rules sample
...
-3
votes
1answer
82 views
How to determine the collection type without access to the source code [closed]
How could you determine if a collection is implemented as an array or as a linked structure without access to the source code (assuming you can run the code)?
2
votes
2answers
150 views
Finding an efficient data structure and/or algorithm
I am tasked with an animated graph based on a timeline, and I am having trouble finding a suitable data structure and/or algorithm that's reasonably efficient. I have a working system suffering from ...
1
vote
1answer
66 views
A table for each field type or one all-in-one table model?
I am creating an application where users can create forms with many fields of text, numeric, date and select types.
The model will have a forms table referenced by responses table;
It also have the ...
1
vote
1answer
91 views
Managing heterogeneous data
The underlying problem is one I seem to run into a lot. You have a collection of objects with some things in common, but other information about the objects may apply to some of them but not to others....
1
vote
1answer
37 views
Dictionary Application: Suggestions for serialization format and data structure
I want to create a dictionary application.
One of the design guideline is performance in querying and showing up the definitions of words.
I would like some suggestions on two design choices:
Which ...
0
votes
2answers
58 views
What are formats to store geographic maps for a robot to travel point A to point B
Very beginner. Need to compute route from A to B for a robot. i would like to know how to store area map and compute the route. I can compute shortest path etc using algorithms e.g. dijkstra. What ...
1
vote
1answer
99 views
Binary Search Tree with ID and Duplicate Values
I'm having trouble finding resources for this implementation I'm trying to figure out. I want to save nodes in a binary search tree (self balancing) containing an ID and value
struct Score
{
int ...
2
votes
2answers
204 views
Can nested loop have linear time complexity
I was going through the traditional quick sort algorithm. I had a look on the partition algorithm in a couple of places and the implementation difference was very subtle. Here are the 2 approaches:
...
0
votes
1answer
64 views
Data Structure to join points by similarity measure
I have a series of points (x,y) and each point has a colour (in the LAB colour space). I need to associate points by similar colour and then spatially. So the end result is each point becomes part of ...
-2
votes
2answers
37 views
database/orm model design for contacts
I am building a internal crm which has contacts which are just people with first name, last name, email, phone etc. Contacts can be one or more types e.t.c. job candidates, hiring managers, customers, ...
1
vote
0answers
46 views
How to use lock-free FIFOs in multi-threading?
Computer-science wisdom says that a lock-free FIFO (queue) is the right way to synchronize shared data between two threads in a lock-free manner. I know what a queue is and how the lock-free property ...
0
votes
1answer
52 views
Subdomain matching
I am working on a small plugin for a DNS server. I have a static list of domain (sometimes subdomains too) names:
gaming.xyz.com
facebook.com
mail.example.com
blog.example.com
I want to check if a ...
2
votes
2answers
109 views
How to model JSON data so it can be easily de-serialized in to simple Java classes?
Context
Currently I'm struggling with correctly modeling a small instruction set I want to send as JSON to an Android application to generate a list of UI parts. Right now it's layered as pretty much ...
2
votes
1answer
82 views
trie iteration should include root?
I'm working on a trie data structure. My simple, initial understanding: trie data structures require a fixed root node. This node cannot be deleted.
When iterating through all nodes in a trie (in ...
2
votes
3answers
175 views
How should I implement custom database fields?
I'm building an app where end users can add custom fields to database tables. Think of it like a CRM app, where sometime you just need to add an extra field to your customer table. Pretty much all ...
0
votes
1answer
129 views
How fuzzy search is implemented for file paths
Say I have file paths like this:
my/long/directory/structure/index.js
my/long/directory/structure2/index.js
my/long/directory/structure3/index.js
my/long/directory/structure.../index.js
my/long/...
1
vote
1answer
63 views
Which datastructure to use for temporary storage of intermittent and asynchronous sensor data?
Here an outline of the setup:
Input data:
I have several sources for sensor input data (GPS, and a bunch of other sensor data from different sources).
All of those individual inputs consist of a ...
0
votes
1answer
99 views
Express unique recursive task system
I would like to express a task as either itself or a container for other tasks (recursively). The problem is that each task has to be one of two fundamental types: a goal or a routine. And, children ...
58
votes
16answers
11k views
How should I store “unknown” and “missing” values in a variable, while still retaining the difference between “unknown” and “missing”?
Consider this an "academic" question. I have been wondering about about avoiding NULLs from time to time and this is an example where I can't come up with a satisfactory solution.
Let's assume I ...
0
votes
1answer
364 views
How would you design a “multithreaded” LRU cache using C++ (unordered_map and Linkedlist)?
Please note that this is about a thread-safe LRU cache (not simply a LRU cache as specified in https://leetcode.com/problems/lru-cache/description/). It isn't a duplicate of LRU cache design question ...
1
vote
1answer
128 views
Find a string in list of strings
Background:
I am writing an application for a small embedded device. There is a static list of strings: currently about 500 strings and string length is 12 characters on average. The list might ...
0
votes
3answers
277 views
how can i return the median of a threaded binary search tree in constant time?
I'm having a trouble with understanding how to implement and find the median of a threaded binary search tree in constant time.
The tree consists of a worker's id and name.
The given details are ...
17
votes
9answers
2k views
How is polymorphism used in the real world? [closed]
I am trying to understand how Polymorphism is used in a real life project, but I can only find the classical example (or something similar to it) of having an Animal parent class with a methodspeak(), ...
2
votes
1answer
142 views
Data Structure for “Intuitive” Text Matching
I've noticed that text editors and such have a more-than-prefix/suffix-based pattern matching algorithm going on behind the scenes. And StackOverflow's tag matching algorithm does more than just ...
0
votes
1answer
63 views
Limitations of Tries in Comparison to B-Trees for a Database
I am wondering about how range queries work, and the standard solution is to use B+trees. However, I am a fan of tries as a general data structure and would like to know if they (or variations of them)...
45
votes
8answers
12k views
Before OOP, were data structure members left public?
When a data structure (for example, a queue) is implemented using an OOP language, some members of the data structure need to be private (for example, the number of items in the queue).
A queue can ...
1
vote
2answers
71 views
Should static and historical data be split in the API? To what extend?
The project is a read-only interface for a company database.
In the database, there is some 'static' data about departments, in a Departments table.
The value of these fields don't change with time (...
4
votes
2answers
130 views
Multiple data structures containing the same references
I was wondering what the best practice is for creating multiple different data structure which can all contain references to the same objects. As an example, consider a video game with many entities.
...
0
votes
0answers
42 views
implementing data structure that consists of pair-diff(s,d)
i am having trouble and would really appreciate your help, especially with pair-diff(S,d)
i am trying to implement a data structure S in given times:
Insert(S,k) - inserting k into S O(logn)
Delete(...
1
vote
1answer
65 views
Parnas' Paper on Modularization and Workflow Engines
In a Software Engineering class, we had an assignment to read Parnas' seminal paper on modularization [0]. In this paper, two approaches of dividing a software into modules are discussed:
Traditional ...
0
votes
0answers
63 views
JSON-based Audit Log best practice
Not quite sure if this is the community to ask this question, but I was wondering what the best structure would be for a JSON-based audit logger.
We currently run Microsoft SQL Server but some of the ...
1
vote
1answer
97 views
How to fetch data based on id from isolated code cleanest way?
I'm working on client-server application. Client architecture (class hierarchy) looks like this:
System (name is of course different, more descriptive) - represents whole system
Module A - a class ...
-1
votes
1answer
113 views
Is Tree the right data structure?
I must create a basic calendar of one year. I thought to use a generic Tree with the year like root, months as children of root, days as children of months etc...
Is it the right way?
I receive data ...
-3
votes
1answer
96 views
Determining MPG over a range of time using Dictionary and Class Objects
A group of friends are tracking the miles per gallon for each of their cars. Each time one of them fills up their gas tank, they record the following in a file:
His or her name, The type of car they ...
1
vote
2answers
1k views
Advantages of using an array over a hash table?
I am wondering about the following question. To simulate an array via a hash table, one can simply set the keys of the hash table to be the indices of the array, and set the value of each key to be ...
1
vote
1answer
44 views
Flexable Table, or multiple tables?
In my application, I have many things that use images in different ways. For example, a product may have a logo and many screenshots, a user can have a profile image, and a company can have a logo.
I ...
1
vote
2answers
200 views
Large matrix manipulation in multithreaded environment
I have:
matrix 20*40000 of floats M - std::vector<std::vector<float>>;
1000 values X;
~2000000 POD structures S.
A typical situation is: for each value from X I take several structs from ...
3
votes
3answers
211 views
Optimal way of storing sorted tree in memory
Wondering what the general structure is for storing a tree in memory most efficiently (for access operation, and space).
For the access operation, it should take advantage of contiguous memory (...
10
votes
4answers
641 views
Good code style to introduce data checks everywhere?
I have a project that is sufficiently large in size that I can't keep every aspect in my head any more. I'm dealing with a number of classes and functions in it, and I'm passing data around.
With ...
0
votes
1answer
49 views
Question about memory handling of trees and certain sorts on large data sets.
If data structures such as trees and certain sorts(quick sort, merge sort) work using recursive algorithms and recursive algorithms take up a lot of memory space in the stack and can only work on a ...
7
votes
2answers
352 views
FIFO Min-Max-Heap for Rolling Median
I'm working on a system with hard real-time constraints in c++ and I need a very fast way to calculate the rolling/moving/streaming median of a set of numbers of size N=100 to 300. Normally this size ...
