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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Entering base characters one-by-one for a List [on hold]

This function should prompt the user to enter bases characters (a, g, c and t) one-by-one and then insert them in the List. ...
6
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2answers
307 views

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 ...
11
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5answers
611 views

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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0answers
20 views

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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1answer
41 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 ...
3
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1answer
33 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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3answers
162 views

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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0answers
30 views

Hacker earth Challenge - Number of Interest [closed]

I am facing a rather humiliating problem. There is a challenge which I have solved but when I submit the code I am getting a score of zero. But it seems to be producing correct output when I am ...
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3answers
64 views

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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1answer
43 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: ...
3
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1answer
37 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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4answers
992 views

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 ...
3
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1answer
52 views

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 ...
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0answers
39 views

Memory Segmentation Simulation

I recently have been working on a project to simulate segmentation in memory. I wanted to create everything from scratch; not use pre-built data structures. I create a memory object that allows for ...
2
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0answers
54 views

Linked list order reverse program efficiency

Here is my function which convert linked list in the following order: Example: Inputs: 1->2->3->4->5->6->7->8->NULL and k = 3 Output: 3->2->1->6->5->4->8->7->NULL. Code: ...
5
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3answers
80 views

Check if a binary tree is balanced

Looking for code-review, optimizations and best practices. This question is attributed to geeksforgeeks. NOTE: Please help me verify space complexity, as I am creating ...
2
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1answer
43 views

Improving time complexity of cheapest travel route algorithm

Below is the code to find the cheapest route for a passenger. stationsUnexplored is a Queue to which stations are added and ...
5
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0answers
47 views

BiDirectional Dictionary (and its Mutable friend can come too)

I've attempted to implement a 1-to-1 dictionary in Objective-C. I'm probably missing some convenient methods that one might commonly want to use. These are both declared in the same ...
2
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2answers
154 views

Is there some way of taking advantage of code reuse in this example?

I am implementing a set, using an array as the backend. Here is how I declared it (and some method implementations): ...
3
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1answer
45 views

Disjoint-set data structure in Python 3

Inspired by this question, I decided to implement a Disjoint-set data structure in Python 3. I mainly followed this description for understanding the algorithm (but did not do the optimizations for ...
2
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2answers
103 views

Bag data structure (a set that can store multiple copies of items)

I am trying to make my class a bit cleaner, especially some of its methods like Count, __add__, ...
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4answers
71 views

Coupon collector

This is a coupon collector code to analyze the running time. I need some suggestions on improving the running times of this code. I have used the data structure dictionary, but is there any other data ...
4
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2answers
91 views

Inefficient hash map operation provokes OutOfMemory: Java heap space error

I know I can increase the size of the heap but that seems like a poor solution. This program runs correctly on small files but when run on large data sets it crashes with the OutOfMemory: Java heap ...
2
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3answers
416 views

Finding duplicates in two sorted arrays

This is an interview question from here. Specifically, the second asked for a function that took in two sorted arrays of integers with no duplicate values within a single array and which returned an ...
5
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2answers
123 views

Data structure to count occurrences of entries

I would love to hear any thoughtful suggestions on how to improve my programming style in order to be more understandable. Listed below is a sample of my code which I wrote in Eclipse: ...
4
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1answer
60 views

Design/reiterate or code reuse for linked list

This is what my class hierarchy looks like. I have an abstract superclass, AbstractLinkedMyList, that contains common operations for both sorted and unsorted linked ...
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1answer
263 views

Order a delicious pie here

For a quick summary: I've created this internal web application, and I've hit a point where I can really see the mess I've made. I need some help separating the logic, the view, and the data. More ...
2
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1answer
59 views

Rewriting linked list function without a NULL variable

This is how my LinkedList class looks like in PHP. I am trying to figure out if I can rewrite my reverse_list_recursively() ...
3
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3answers
88 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 ...
3
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1answer
59 views

Least common ancestor (LCA) in a binary tree

Find the LCA in binary tree, where a node is also its own ancestor. This question is attributed to GeeksForGeeks. I'm looking for code review, optimizations and best practices. ...
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1answer
90 views

Finding the shortest substring containing keywords

Problem: Write a function that takes a String document and a String[] keywords and returns the smallest substring of ...
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4answers
482 views

Recursive binary search tree - follow-up

This is a follow-up to Recursive binary search tree changes: Used raw pointers rather than std::unique_ptr const correctness Made variable names more beautiful implemented at() How can I improve ...
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3answers
473 views

Preorder, inorder, postorder for tree in C++11

Please review my code for preorder, inorder and postorder of a tree. I am using C++11 (or wanted to use), so let me know if anything is deviating from the C++11 standard. ...
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0answers
49 views

Hash Table Implemented by Javascript

I recently tried to implement a simple hash table using Javascript. Could anyone help me review my implementation? ...
2
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2answers
99 views

Counting a cycle

An interview question I got - Each element of an int array points to the another element, eventually creating a cycle. Starting at ...
4
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1answer
76 views

Circular linked list in C

Let me know if it seems right to you and if anything can be optimized. My concern is that I'm unsure if circular linked lists are supposed to have a tail. I've implemented it just using a head. Is ...
2
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2answers
70 views

Doubly linked list code in C

Let me know if it seems right to you and if anything can be optimized. ...
3
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1answer
88 views

Circular queue implementation using two regions

Inspired by the "bip buffer", I coded a fixed-size circular queue that uses two regions (two pairs of begin/end pointers) to account for the wrap-around. The main goal of this design was to simplify ...
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0answers
71 views

Binary heap with O(1) lookup and O(log n) change key

I needed a priority queue that allowed efficient searching and changing of keys. I tried std::priority_queue, but the interface was extremely limiting. Not being ...
5
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2answers
128 views

Find if a word with wildcard exists in dictionary [closed]

This is a question from a phone interview I had. The question was in 2 parts: a. find("cat") -> T/F suggest a data structure to find is if a word exists in a large dictionary, how will one node ...
8
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1answer
125 views

Networking in iOS Swift

This piece of code is working - It gives me a lot of JSON back, which I have yet to parse, but I'd like to show my code here first to get tips on how to improve what I already have: ...
2
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1answer
155 views

Graph implementation adjacency list 1.0

Please note the following: All edges are directed Removal of edges/nodges is not implemented yet A user of the class Graph can never (hopefully) access a ...
5
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1answer
110 views

Find all the paths of tree that add to a input value

This code is attributed to Stack Overflow itself here. The path which adds to the sum, which need not be starting from the root, not be ending at the leaf, i.e. a path can be between root and a leaf. ...
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3answers
98 views

Removing duplicates without using a temporary buffer

This question is from Cracking the Coding Interview and in this question they have asked to solve without using temporary buffer. I have used Iterator interface. Can I use it or need to re-implement ...
8
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2answers
137 views

Simple Linked Hash Map in JS (node/browser)

I needed a simple data structure to cache the most recent few directory contents for this project I was working on. I thought a Linked Hash Map would be the right approach since we will cache only one ...
6
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2answers
281 views

HashTable implementation

I have been trying to implement the Hash Table function in Java and here is what I came up with. I would just like to get an opinion on this work. Would there be a better way or any improvement to ...
0
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1answer
115 views

Implementing a stack using a simple array, dynamic array and linked list

I have implemented a stack using simple array, dynamic array and linked list. I am requesting a review of this code. Interface for stack: ...
3
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1answer
94 views

Deepest node in tree

I have written two classes, one to represent the tree and a Util class to get the deepest node from the tree. Can you please review the code? Below is the class ...
3
votes
1answer
82 views

AVL tree implementation in C

I have an assignment. I need to write an AVL tree. This is what I have written so far. It works on all of my tests, but suddenly fails in checking system with TL(time limit exceeded). Personally I ...
4
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3answers
235 views

Custom SkipList implementation in Java

I recently studied SkipList and thought i would create one on my own. This implementation uses a 2 layer Skip list where the size of the support list is roughly square root of the size of the original ...