A data structure is a way of organizing data in a fashion that allows particular properties of that data to be queried and/or updated efficiently.

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Isomorphic Strings

Two strings are isomorphic if the characters in s can be replaced to get t. Can efficiency be increased further for this code? ...
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Speed up large calculation of intersections

I have the following data: trains is a dictionary with 1700 elements. The keys are the IDs of trains and the value for each train is an array with every station ...
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37 views

Linked List Operations in C Read Proof

I am trying to write up all the linked list basic operations (push, pop, add_at_end, pop_from_end, add_at_index, pop_from_index). This is not a school assignment, even though it may look like one. I ...
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A map class based on an AVL tree

Here's an implementation of a class which is similar to std::map, but it's not a complete/identical implementation. I know C pretty well, but am a beginner with ...
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Data item prototype in a Javascript data structure where object instance functions see own data

I'm working on a complex Javascript application which includes its own data structure. The previous version's data structure was rather chaotic, and I'm looking to replace it with something where: ...
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86 views

Self Implemented Hash Map Performance

I have written two hash map implementations, one that stores Vertices and one that stores self implemented vectors of Edges. They are all fully functioning, however in my application they are quite ...
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Container with allocator copy assignment

I am trying to write a simple Buffer container class that will behave like std::vector. It should construct only elements that ...
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42 views

Graphs processing in Scala

I've just started to learn Scala and decided to implement small graph library to train. Here is the basic version, that describes graph and nodes structure and also provides implementation of ...
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Building in the built-in declarations

In order for Rubberduck to be able to "recognize" the built-in VBA functions, procedures and objects, I added yet another constructor parameter to my Declaration ...
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86 views

Better method structure for insertion in doubly linked list

Here is my insertion method for a doubly linked list. It works, but passing two parameters for the method seems cumbersome. Can anyone suggest a cleaner approach than this? ...
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C code to represent a dataset and a 'window' of data

I'm fairly new to C so I'm looking to see if I'm heading in the right direction. This bit of code is to define a structure which represents a dataset (in this case, a GDAL dataset and some ...
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Suffix array construction in \$ O(n \log^2 n) \$

Here is my implementation of the suffix array construction algorithm which follows this paper (specifically, pages 4 and 6). ...
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171 views

Suffix tree implementation in Java

I was trying to solve the problem where given a larger string and an array/list of smaller string, we need to make the determination whether the larger string contains each of the smaller strings. I ...
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1answer
37 views

Minimal Map implementation with weak values

What follows is an implementation of the java.util.Map interface with weak values. This means that entries should be removed from the map when their values become ...
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72 views

Simple stack and linked list

I know that Python has a built-in list data structure, but I want to implement my own linked list and stack data structures for practice. I have three classes ...
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44 views

Max-heap implementation with List

I am trying to create max-heap for practice. Are there any bugs? Are there ways that I can improve the code quality? ...
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1answer
144 views

Torus Maze Generator

I have been working on a project to randomly generate a torus made through the use of an adjacency list and disjoint set structure (to be extended to solve the maze later), made from scratch. I think ...
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2answers
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Find non duplicate Triangle Triplets from a list of given numbers- version 3

It is a continuation of my previous question: Find non duplicateTriangle Triplets from a list of given numbers After I realized triplet structure using less space than ...
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Graph adjacency list implementation in C++

I have been playing around with an adjacency list implementation of a graph class, on which I'd like to be able to run a build and test several graph algorithms. The code I have below works and I have ...
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Array of pointers data structure

Does this data structure make sense? It's essentially a vector of pointers, intended to point to larger objects. In effect, it gives the benefit of a linked list, with an \$O(1)\$ lookup at the cost ...
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126 views

Double-ended linked list

I want to know if there is any redundancy in the code or if it is missing something. I ran it with several different choices and it works fine but I still want to know are there any more subtle ...
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1answer
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Common operations on a linked list (user defined)

I have just started learning data structures and for the past two days I was going through linked lists. I have implemented the basic/common operations on the linked lists and I would love for some ...
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Suffix Array Construction

I'm trying to implement a suffix array for use in programming competitions. I'm using the CodeForces example and trying to "make it my own" so I can make sure I understand it and feel better about ...
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Quack - the revolutionary new data structure

I was having a chat with a friend about data structures (as you do), and that, and his love of portmanteaus meant that he came up with a Quack - A queue and a ...
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69 views

Determine the index where two lists diverge

Background A class provides an API to determine the index where two string lists diverge. ...
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Check is_permutation on a pair of same sized arrays

After considering the suggestions of my previous question Check whether given a pair of arrays are permutation of each other, I changed the code. Resolved the bug reported earlier In place of ...
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Check whether given a pair of arrays are permutation of each other

Check whether two given arrays are permutation of each others. Does this implementation guarantee execution of \$O(n)\$ time? What is the additional space utilization for this implementation by ...
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Object pool with linked list of available objects implementation

I was reading some gameprogrammingpatterns (awesome book, by the way, would recommend) and was very excited when I learned that unions are a thing that exists, so I decided to implement an object pool ...
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Create pairs from a set of numbers

Problem here is to list all pairs from a set of integers. We need 2 versions. In the first program, the order matters — pairs (a,b) and (b,a) are considered distinct. In the second program, (a,b) and ...
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Univariate polynomial multiplication using Doubly Linked List

A univariate polynomial is a polynomial over a single variable, and in the following discussion when we say polynomial, we mean a polynomial in a single variable. You are given two polynomials ...
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Simple binary heap in C#

I've written a simple binary heap in C# and I want to know if it has any problems or if I can make it better. ...
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688 views

Quadtree implementation

I've implemented a quadtree in C++. Ignore any apparent similarity to the pseudocode on Wikipedia, it's all in your head, I swear. How can I improve? Algorithm speed/space improvements, any extra ...
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1answer
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Binary Search Tree in C

I have implemented a BST from scratch. My aim is to draft better code and understand some pitfalls which I may have overlooked. It includes the following functionalities: Insert a new item. Find ...
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Java Trie structure

I recently have been working on a Trie in Java. I have looked at the related posts here on Code Review to try and enhance my code, but I do have some methods and constraints not present on other ...
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115 views

Constructing and maintaining a complete binary tree

Problem statement: Create and maintain a Complete Binary Tree in C. Include the following operations. Insert a given key and perform inorder Replace ALL occurrences of the given key ...
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Designing another Coffee Machine Application

After reading Designing a coffee machine yesterday, I decided I could also give the same problem a try. I have used the following problem statement (copied from the given question): Design a ...
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1answer
81 views

3-stack implementation with a single array

I'm teaching myself data structures and would really appreciate some feedback on my stack implementation. A couple of things I'm not sure if I should be doing: creation of the array and pointer ...
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Designing a coffee machine

I was recently rejected from what looked like a really promising string of interviews. I did very well in a questionnaire style review, and then they handed me this assignment (more or less): ...
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C++ Linked List Implementation

I'm learning C++ and also about data structures, so I am trying to implement some. This is my linked list. I've included two different ways of getting the length of the list, with a ...
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Singly Linked List in Java

I created my own implementation of a Singly Linked List. Is there anything I can improve on, in terms of effciency. Also, what other methods would you recommend for me to try and implement. My goal is ...
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Extract and rename specific columns of a CSV data file

I have a CSV data file with 3,896 columns (variables), and I am attempting to extract a particular subset of columns for use in a data analysis project. To avoid the burden of having to constantly ...
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100 views

Prefix trees for auto suggest

I wrote a quick prefix tree implementation. I know it may be far from perfect, but I need to make sure that I got the basics right. My main concerns are: Have I settled for the correct data ...
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1answer
1k views

Depth First Search and Breadth First Search in C++

I am trying to learn DFS and BFS. However, I just want to make sure that I am not doing anything wrong. Would you please determine if the BFS and DFS functions are correct? ...
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Return list of common email ids from a list of lists

Input: ArrayList of ArrayLists with email ids. Output: Return ArrayList of email ids which appears in each inner ArrayList. Ex: Input: [[abc@gmail.com, ...
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Finding all integers in an array with odd occurrence

I am doing an interview exercise problem from here. The problem is to find "all numbers that occurred an odd-number of times in an array". Here is my high level psuedo code thinking: Construct a ...
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70 views

Data structure for inserting and replacing data in list

I have a list of key value pairs, that is used as an intermediate store for building URL parameters or JSON data. Currently this is done with a linked list: ...
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51 views

Perceptron algorithm

This is the Perceptron algorithm, I wrote this implementation with my friend. It gets the job done, but it's quite dirty, perhaps one of you stylish hackers might help me beautify this beast. This ...
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Smart as a bag of rocks

For my second project in CS2, I was given the following assignment: Implement a new ADT called a bag with receipts. The specification for the class of bag with receipts differs from a ...
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Trie Implementation in Java

I am trying to implement a Trie class in Java which just supports insertion and searching operation up until now. I think it works perfectly on the several examples ...