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Questions tagged [collections]

Collections APIs provide developers with a set of classes and interfaces that makes it easier to handle collections of objects.

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2 votes
1 answer
74 views

Generic container wrapper type with a default underlying buffer (2nd rev)

This is a revision of the previous question. I was told to ask an additional question with more context for the modified code to be reviewed. The changes: changed from ...
2 votes
1 answer
55 views

Looking for feedback on a flavour of Radix tree I wrote. This is version 2 of the class original posted on this forum

My project explores some ideas i've had regarding alternate data structures to the unorderd_map and map, and aiming the exploration to key sets with a non uniform distribution and key sets with common ...
4 votes
1 answer
186 views

Looking for feedback on a flavour of Radix tree I wrote. The idea is speed on find() time if keys share common prefixes and are known ahead of time

My project explores some ideas i've had regarding alternate data structures to the unorderd_map and map, and aiming the exploration to key sets with a non uniform distribution and key sets with common ...
2 votes
1 answer
47 views

A collection based on a bitset to store a set of unique integers from a given range (rev. 3)

All right, let's do this one last time. This is continuation of this review. I applied most of the proposed changes, making interface of my container very close to that of ...
4 votes
1 answer
75 views

A collection based on a bitset to store a set of unique integers from a given range (rev. 2)

This is a continuation of this review. I applied most of the proposed changes. These changes were focused mostly on decoupling the class from the rest of the program and making its interface more like ...
1 vote
1 answer
79 views

Collection that uses a bitset to store a huge set of unique integers from a given range (rev. 1)

Some (skippable) context: I'm writing program that minimizes an arbitrary logical function. Such function takes an unsigned integer as an argument and returns either ...
2 votes
3 answers
109 views

A dynamic array with an iterator compatible with std::sort

I wrote a Vector (dynamic array) class with an iterator usable with std::sort() . It seems to pass my tests. I wondering about the issues one can spot on this ...
1 vote
1 answer
101 views

SynchronizedObservableCollection: a thread-safe ObservableCollection

After reading many people talk about the need for a SynchronizedObservableCollection and their implementations I decided to roll my own. I wanted to add a ...
2 votes
2 answers
2k views

C++ ring buffer using some C++ 17 and coming C++ 20 std::span

When I heard about the new Linux I/O interface io_uring I searched about the ring buffer. I then thought I may replace my safe queue which is base on C++ 11 ...
4 votes
2 answers
1k views

C++20 "FixedArray" Container (dynamically allocated fixed-size array)

I've wrote a FixedArray to fit seamlessly (function-wise) with the default C++ containers, including working with algorithms/etc. It is a dynamically allocated, but fixed size array. Code ...
3 votes
1 answer
124 views

std::list reimplementation for practice

I used cppreference list to implement this simplified std::list. The CXX_STANDARD is 11. My questions are the usual: Is the ...
1 vote
2 answers
649 views

Implemented Sorting of Map by Value and then by Key in java

So I had this requirement to get the frequency of names appearing in a list and then print the one appearing the most number of times. If there is a clash, print the one which comes first in the ...
5 votes
2 answers
4k views

Bidirectional map based on memory manipulation

This is a bidirectional map implementation that stores the values as pairs on the heap, and uses pointer arithmetic for efficient lookup. codepad link, may be easier to read ...
3 votes
6 answers
10k views

Divide group of numbers into two groups of which the sums are equal

I have a piece of code that divides a group of numbers into two groups of numbers of which the sums are equal. I created this because of a Stack Overflow question: For example: {10,15,20,5} will ...
3 votes
2 answers
392 views

C macro based dynamic array library

This library is a fork of eteran/c-vector. It is macro based, so that it is generic, without void pointers and additional functions. This of course means that it has the downsides of macros in C. The ...
4 votes
2 answers
140 views

Sort a dict by keys, assuming keys are orderable

I found a suspicious code snipped in an existing project in which I am involved as a developer. The code sorts a dict by its keys, so that if iterated over the dict,...
3 votes
1 answer
440 views

Yet another sparse set implementation

I got inspired by this blog post and implemented a fixed-size sparse set, removing the need for vectors, because the sparse set's size equals at least ...
6 votes
2 answers
1k views

A not so simple C++20 circular queue

This container reduces the number of memory allocations on queue-type operations (push + pop) compared to std::deque. Basic performance tests indicates a performance similar to std::deque where main ...
2 votes
1 answer
234 views

Simple C++ circular queue

I wrote a simple C++20 circular queue. https://github.com/torrentg/cqueue Here is cqueue.hpp ...
8 votes
3 answers
5k views

Piling Up with Python

This is my solution for a Hackerrank problem. The problem was: There is a horizontal row of cubes. The length of each cube is given. You need to create a new vertical pile of cubes. The new pile ...
0 votes
1 answer
48 views

Iterating over JSON more effectively

Problem: I need to get data from JSON file containing information about "contributors". Each contributor has an atrribute jobs, which is a list of string-...
1 vote
1 answer
108 views

Class that wraps a collection and tracks if its elements were visited

The VisitedCollection is a collection wrapper for setting and tracking if elements were visited (removed in terms of the wrapper) I have concerns regarding: should ...
2 votes
3 answers
167 views

How to efficiently build an object from list or array of strings

I am working with an API that delivers some data in a QStringList or basically a list of strings. The data contains keys and values but it is not a ...
0 votes
1 answer
1k views

std::list implementation learning exercise

I want to improve my algorithms and data structures in C++ understanding and also learn how the standard library containers are implemented. I implemented a std::vector in a previous review and this ...
0 votes
1 answer
2k views

Faster way to find items from one list in another one [closed]

I would like to check if a string appears in a list of strings. For that, I have chosen the List<string> type, as follows: ...
5 votes
1 answer
298 views

C smart string implementation using preprocessor

I have wrote a smart string container implementation for use in my application, but as I'am not such professional C programmer I have doubts about is I'am did it right and is there ways how to improve ...
5 votes
2 answers
203 views

std::vector implementation learning exercise

I want to improve my algorithms and data structures in C++ understanding and also learn how the standard library containers are implemented. This resizing_array is based on the std::vector. My ...
1 vote
0 answers
1k views

Spring Boot Integration Test with SQS and Elastic Search

I have the following integration test that starts with sending message to sqs queue and ends with checking elastic search if the associated object added to db. The part of application I want to test ...
-1 votes
1 answer
81 views

Most efficient way to track a collection of targets in range of a source object [closed]

In my game there are space ships and each of these space ships tracks which other ships are in range of it. I need to perform certain logic when a target ship comes in range of another ship, and ...
0 votes
1 answer
240 views

Action on each element of an inline list

I'm trying to learn the "functional" part of C#/.Net for work, and I'm not sure if this is a good way to write this statement. I was also trying to reduce duplicated code while not ...
3 votes
1 answer
87 views

C Typed Vector that implements type-safety, encapsulation and lazy initialization

C Typed Vector I wasn't happy with the various dynamic array / vector implementations in C, so I made my own. In general, I'm not the biggest fan of C-preprocessor madness, but alas for this ...
3 votes
0 answers
230 views

Implementation of Dynamic Array with allocators and C++20

To train my skills in C++, I decided to implement the well-known "Dynamic array" data structure on my own. I realized early on that using pointers or smart pointers is wrong, as it leads to ...
1 vote
0 answers
2k views

Implementation of Doubly Linked List with sentinel in C++ trying to replicate the stl std::list [closed]

I am currently trying to replicate the STL std::list interface with my own list implementation (doubly linked list with sentinel) to learn about all the advanced ...
3 votes
2 answers
407 views

Prime numbers iterator

I am not familiar with iterators. I am confused with the traits approach and the traditional one. I don't know which one I should use in 2021. I wrote a minimal ...
7 votes
1 answer
337 views

Custom implementation to provide an immutable range of a container without copying it

I needed to pass a const reference to part of a std::vector without copy. I posted the previous version in my earlier question, thank you for the great support! As ...
13 votes
1 answer
243 views

Multi-function memoizator and multi-type container

I'm trying to write a multiple functions memoizator, which I've talked about here. The main problem is creating a container containing different and heterogenous functions. I found a working solution,...
1 vote
2 answers
105 views

Is there a way to simplify getting the character that appears the most in a collection with Linq?

I have a collection of strings, all of which are three characters in length: ...
4 votes
2 answers
2k views

Implementing an HotelManager interface in Java

Got a mission to implement an Hotel Manager interface. I will post the interface and the attached class Reservation, and will add my code. What I am asking you is ...
2 votes
1 answer
1k views

Python script to automate the creation of Linux LXC containers

Like the title suggests, I wrote a script in Python that uses the python3-lxc library to automate the creation of Linux LXC containers. I realised that containers ...
3 votes
3 answers
479 views

Efficient way of flat mapping a range of a multidimensional random access collection

I've recently answered a question about reading elements from an array of arrays. A way it could be interpreted is that the OP wanted to read a range that could span over multiple subarrays of the 2D ...
3 votes
1 answer
62 views

Dependency Container

I'm currently creating my own microframework for learning purpose and I want to make it more powerful by providing a way to register classes and instantiate them (once) only when needed. So here is my ...
1 vote
1 answer
988 views

A multi key/value type "folded" map class template

I have recently come across a use case where I need to lump many maps into a single container. These maps can have different combinations of key/value types, but they all differ from one another. For ...
1 vote
1 answer
78 views

R Container for Multiple data.frame with a Brief Description of the Content of the data.frame

For a project I have a large dataset with a multitude of variables from different questionnaires. Not all variables are required for all analyses. So I created a preprocessing script, in which subsets ...
5 votes
2 answers
2k views

Hash table implemented in C with open addressing

While posting this, I noticed there are quite a few similar C hash table implementations here already. So I figured one more wouldn't hurt. :-) In any case, I'm writing a teaching article on "how ...
3 votes
1 answer
354 views

Take element of a Set collection depending on the value of another element

I had to populate the fields of a Service object using a Set (HashSet) with any configuration parameters -> ...
2 votes
1 answer
42 views

An exercise concering Kotlin Set

Task description: Declare a function twoInThree(a: Set, b: Set, c: Set), which returns the set of all elements, which are contained in exactly two of the three given sets a, b, c. My solution: ...
4 votes
1 answer
103 views

Data set with many variables in Python, many indented dictionaries?

I am working with a data set that has many variables. Currently I am storing the data in many indented dictionaries in the following way: ...
2 votes
1 answer
955 views

Generic hashmap with dynamic resizing and collision handling

This is a (more or less) continuation of a previous post I made: Generic implementation of a hashtable with double-linked list. I got lots of valuable feedback, so I decided to rewrite the entire ...
2 votes
1 answer
142 views

Print the App Name Using Latest Version

I am trying to solve a problem, where we are given an app name, service name, and version number of an api. We need to print the name of app, which is using the latest version for most of the service. ...
2 votes
1 answer
941 views

Generic Doubly Linked-list implementation in C++

I am just learning about C++ templates and generic types, I decided it would be nice to try to create a generic container class as a challenge and test my knowledge in the process. Here is what I have ...

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