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

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Efficient top k words using MultiMap (Google Guava ext lib JAR)

Basic algorithm: Open document/huge text file Use Map and List to separate the words. \$O(K)\$ time complexity (TC) ...
3
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2answers
58 views

Loop through column cells and compare value with a Collection

I have a Collection of 166 elements: ...
0
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0answers
77 views

Custom ConcurrentHashMap for ints

I've implemented a concurrent hash map for int primitives. ...
3
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1answer
56 views

Removing an object which is wrapped in another object from a collection

I have Clips that can be added to or removed from any number of Lines. When I add the Clip, ...
7
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3answers
103 views

Writing a program to read a maximum of 99 elements in an iteration from a list

I want to read a list of elements and pass a maximum of 99 elements to a function for some logical operations. I have tried this with an array as an example and this code was successful in achieving ...
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1answer
39 views

Properly managing a collection from deserialized XML file throughout app's lifetime

I'm developing a WinForms app to manage some settings and profiles for multiple video games. The list of video games is specified by the user, and I'm trying to figure out how to properly maintain ...
2
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1answer
16 views

GroupBy field with and without white spaces

I have these invoices listed: ...
2
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3answers
104 views

Is one-sided equality more helpful or more confusing than quick failure?

My question is about the equals() method. Most people implement equals() to start like: ...
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2answers
648 views

Optimize method to iterate to over Map<String, List<Object>>

I have a Map<String, List<Object>> multiFieldMap and I need to iterate over its value set and add the value to ...
5
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0answers
72 views

Storing collections of objects of any type

I've put together a class whose goal is to store objects of arbitrary type, with each type having its own vector for contiguity. I'd like to gather advice on what I have so far before I carry on. Let ...
2
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2answers
119 views

Observable Collection “Deep”

In a project of mine I needed a class "Document" to be able to notify any change in its fields. This class keep a collection of class "AnotherClass". Using an ObservableCollection for this collection ...
2
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1answer
79 views

Fixed size double-ended queue

I require hundreds of equal, small sized buffers in my current project. The bulk of the computation in the program operates on data stored directly in those containers, so high performance is ...
3
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2answers
72 views

Simple medical collection/database about patients visits

I am writing a system for doctors who are regularly visited by patients. The doctor adds each patient's visit to collection/database. The class can save data to an .xml file and restore it. Can you ...
3
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2answers
123 views

C# Tree implementation

I’m working on a C# implementation of a tree class. The tree will be used wherever I need to store data in a tree format. (Application Menu, File Infos etc.). Therefore the tree should support a lot ...
5
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1answer
244 views

Hacker Rank: Extracting digits from a given number and check for divisibility

The problem in question is a coding challenge from Hackerrank: Problem Statement You are given an integer N. Find the digits in this number that exactly divide N (division that leaves 0 as ...
2
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1answer
47 views

The information system of the institution

I've made a small project from my institute. I've got 5 classes, in 4 of the classes (Teachers, Students, ...
4
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1answer
87 views

Union of intervals

I am trying to solve for the problem with a bunch of intervals: (1,2),(2,5),(4,7),(9,11) I find their union, which in the above given case would be: ...
0
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2answers
374 views

Array to Tuple in Swift

I am burdened with the requirement of interacting with a C based library, which has a bunch of constant sized arrays (e.g. char[17]). When trying to assign or read ...
8
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3answers
210 views

Collection that can be modified in a foreach

Sometimes you want to add/remove items from a collection inside of a foreach loop. Since this isn't possible, a common pattern is to add the items to a separate ...
4
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3answers
113 views

Thread safe cache for write through and writeback

This cache is like a list where new elements are inserted in the middle, cache hits are put to head of the list and replaced elements are taken from the end. Would I just use a list the lookup would ...
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0answers
37 views

NonEmptySortedSet implementation

I'm looking for feedback specifically about what I might add to this to make it more usable or general, especially with regard to scala collection traits to implement. ...
4
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3answers
1k views

Generic sum method for a Collection<Number>

While answering this question, I wanted to use a generic sum of Collection function. Java doesn't have a native method, so I wrote one. There are a couple things ...
8
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2answers
220 views

Efficiently create and sort a Collection

The goal of my code is to sort data into two categories. It must use a local copy of the initial data from Collar (Top View).csv. My code creates a Collection of items called Collars using the initial ...
3
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2answers
716 views

Word Ladder Solution in Java using ArrayList

Word Ladder Given a start word and a goal word, convert the start word to the goal word by changing one letter at a time. Each step must also be a valid word. Is my code modular? I mean are ...
4
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1answer
89 views

C++11 lock free collection similar to std::forward_list - follow-up

Thread safe and lock free collections are very hard to write, so I'd appreciate any feedback, especially regarding bugs. The code below is a self contained cpp including some tests. This question is ...
3
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2answers
472 views

Wiring CollectionView and grouping it without slowing it down

In my previous question, I got heaps of good advice BUT no solution for the problem apposed. I applied the valuable learnings from the past on this.question and am also hitting it from a different ...
3
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3answers
315 views

Find intersection of two arrays without duplicates

A = [9, 1, 4, 2, 5] k unique integers B = [3, 1, 8, 7, 6, 5] n unique integers Intersection => [1, 5] Find an algorithm that uses \$O(1)\$ space (the space used by the return variable is not ...
3
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3answers
356 views

Implementing a singly LinkedList and IList interface

I have implemented a LinkedList in C#. What would you change/make better? What naming conventions are misused? What would you add? Some of my ideas are to make it ...
2
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2answers
46 views

Remove list of files from another list of files by their name

In groovy I have a list of files A and also another list of files B. I want to remove all the files from A that have a filename that also occurs in the list of files B. I wrote the following code: ...
4
votes
1answer
113 views

C++11 lock free collection similar to std::forward_list [closed]

I'm new to explicit memory ordering, and any kind of thread safety is hard to implement right to begin with. Please let me know if you see any problems, or have suggestions for improvement. Written in ...
4
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2answers
553 views

Subsorting with multiple Comparators

I've seen a number of questions on Stack Overflow of the kind of "How do I sort on fields X AND Y?" The most common answers to those questions consists of "Write a custom Comparator." But what if you ...
11
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4answers
497 views

Collection with both Set and List interface

Here's something I wrote a while ago. I needed a collection that was ordered, but also guaranteed duplicates did not occur. So I made a class with both Set and List interfaces. It seems to work ...
6
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3answers
190 views

Extension method to enumerate a hierarchical object

I have a domain object that I have no control over which itself contains a collection of this same type. This is a classical hierarichal representation like in a tree node hierarchy. I would like to ...
4
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1answer
115 views

Container adaptors

How to improve the functionality, exception safeness and other aspects of the following container adaptors? Allows to write more generic code (not working for, say, ...
2
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1answer
327 views

ArrayList for Shop implementatin

Problem statement: Design a system for the following scenario: An item list contains item code, name, rate, and quantity for several items. Whenever a new item is added in the list ...
7
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1answer
54 views

Joining collections… because it's fun

I'm working on a LinqEnumerable class (reviewable here), and I'm no Big-O expert and I'm pretty bad with algorithms, so I wonder what the complexity is for what ...
-1
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1answer
2k views

ArrayList implementation in C [closed]

Although I know I can use calloc then realloc to make a dynamic array in C, and that I also need a variable to keep track of the ...
2
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2answers
757 views
3
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2answers
117 views

Performance enhancement for collection manipulation

I have below snippet of code which gets all the available menu items for a zone(top or left)and adds the widgets for which user has access to an ArrayList collection. For now the ...
7
votes
2answers
166 views

Array-like container for uints shorter than 8 bits (Rev 1)

This is a follow-up to Array-like container for uints shorter than 8 bits In short: The PackedBitfieldArray should be a kind of container for packed (unsigned) ...
11
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1answer
152 views

Array-like container for uints shorter than 8 bits

Follow-up: Array-like container for uints shorter than 8 bits (Rev 1) First of all: yes, I need this kind of array to generate data for a piece of hardware, and it must be stored and manipulated ...
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2answers
101 views

LinkedVector : a vector of elements with links to other elements

I wanted to have a vector with usual values and with some sort of indexing : an element can have links to other elements (via indices). Something like the following, where ...
10
votes
1answer
296 views

Container with sorted by multiple keys

From this question: Sorted vector (aka flat_set) for objects (pointers) with custom embedded key (functor used) This is an example of a multi-index container. Note: this is not a container as ...
5
votes
3answers
169 views

Finding the closest value in a collection in a game-server plugin implementation

I have an array of a instances of an enum type. A random double variable is initialized with a value between 0.... to 1, and should be used to get the closest ...
5
votes
2answers
536 views

Concurrent Linked Hash Set

Basically I want to create a concurrent LinkedHashSet which returns proper size too. I am mainly concerned about adding and removing iterations. Suggestions ...
5
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2answers
166 views

UniqueList Class in VBA

I often find myself abusing dictionary objects just for the exist method like this, ...
11
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3answers
800 views

Building a better Collection. Enumerable in VBA

VBA's 'Collection' is.... lacking, so, I've been working on a better Collection object that implements many of the features of C#'s Enumerable. This is very much inspired by this question and a follow ...
5
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2answers
413 views

Reducing the execution time of Online Community-Even Groups challenge

I have a coding problem for which I have attempted to solve with the below coding. However, my program is assessed as too slow in its execution and thus needs to be optimized to reduce the execution ...
10
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2answers
808 views

Sorting a collection

Related to, but not exactly a follow up of this question. After fixing some issues discovered in the last review, I added a little more functionality to the ...
8
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3answers
190 views

More imitation of Enumerable in VBA

I was inspired by Me How's question to see how far I could push an imitation of .Net's Enumerable Class. The new functions can obviously handle Collections, but can also handle any collection-type ...