All Data Structures Solutions on Gang of Coders

Total of 254 Data Structures Solutions

Good algorithm and data structure for looking up words with missing letters?

AlgorithmData Structures

How does 3D collision / object detection work?

AlgorithmData Structures3dCollision Detection

Check if a binary tree is a mirror image or symmetric

AlgorithmLanguage AgnosticData StructuresBinary Tree

What is the best way to create a sparse array in C++?

C++OopData StructuresHashMaps

Is there a "Set" data structure in .Net?

C#Data StructuresSet

Implementing a HashMap in C

CData StructuresHashmap

Learning Algorithms and Data Structures Fundamentals

AlgorithmData Structures

Does standard c library provides linked list etc. data structures?

CGccData StructuresGlibc

Whats the difference between objects and data structures?

JavaOopObjectData StructuresLanguage Agnostic

KDTree Implementation in Java

JavaData StructuresKdtree

Which data structure would you use: TreeMap or HashMap? (Java)

JavaData StructuresMapHashmapTreemap

What is the Zipper data structure and should I be using it?

Data StructuresFunctional ProgrammingTheoryZipper

C - How to implement Set data structure?

CAlgorithmMathData StructuresSet

Removing elements from a list containing specific characters

PythonListData Structures

Why exactly do we need a "Circular Linked List" (singly or doubly) data structure?

CData StructuresLinked ListCircular List

Java collections maintaining insertion order

JavaData StructuresCollections

Computing an md5 hash of a data structure

PythonData StructuresMd5

Why hashmap lookup is O(1) i.e. constant time?

Data StructuresHashHashmapHashtableBig O

Algorithm/Data Structure Design Interview Questions

AlgorithmData Structures

Relative performance of std::vector vs. std::list vs. std::slist?

C++Data StructuresStlPerformanceLinked List

Stack and Queue, Why?

Data StructuresStackQueue

How is vector implemented in C++

C++Data Structures

Alternatives to Entity-Attribute-Value (EAV)?

DatabaseDatabase DesignData StructuresData ModelingEntity Attribute-Value

How to implement 3 stacks with one array?

AlgorithmData StructuresStack

Stack with find-min/find-max more efficient than O(n)?

JavaAlgorithmData StructuresStackBig O

data structure used to implement UNDO and REDO option

Data StructuresDesign PatternsUndo Redo

Data structure for text editor

Data StructuresText Editor

What are "sums-and-products" data structures?

Data StructuresProgramming LanguagesTypesType SystemsAlgebraic Data-Types

What's the best way to return a pair of values in Java?

JavaData Structures

Efficient implementation of binary heaps

C++Data StructuresPerformanceComputer SciencePriority Queue

Difference between AVL trees and splay trees

AlgorithmData StructuresBinary Search-TreeAvl TreeSplay Tree

Mastering Recursive Programming

AlgorithmRecursionData StructuresRecursive Datastructures

Circular buffer in JavaScript

JavascriptData StructuresCircular Buffer

Is there pointer in C# like C++? Is it safe?

C#C++Data StructuresTree

How can I implement a tree in Python?

PythonData StructuresTree

Queue vs Dequeue in java

JavaData StructuresQueueDeque

Does VBA have Dictionary Structure?

VbaDictionaryData StructuresVb6

What are good examples of problems that graphs can solve better than the alternative?

Data StructuresGraphGraph Theory

Doubly Linked List in a Purely Functional Programming Language

Data StructuresHaskellFunctional ProgrammingLinked List

Text editor theory

Data StructuresEditorText EditorTheory

What is the distinction between sparse and dense graphs?

Data StructuresGraphGraph Theory

Binary Search Tree - Java Implementation

JavaData StructuresTree

Ukkonen's suffix tree algorithm in plain English

StringAlgorithmData StructuresLanguage AgnosticSuffix Tree

Tree data structure in C#

C#Data Structures

How to convert List to Map?

JavaListData StructuresHashmapData Conversion

Skip List vs. Binary Search Tree

AlgorithmLanguage AgnosticData StructuresBinary TreeSkip Lists

Why doesn't java.util.Set have get(int index)?

JavaData StructuresCollectionsSet

What is the difference between a map and a dictionary?

DictionaryData StructuresLanguage AgnosticKey Value

Priority queue in .Net

C#.NetData StructuresHeapPriority Queue

golang why don't we have a set datastructure

Data StructuresGoSet

Python Sets vs Lists

PythonListPerformanceData StructuresSet

Why should I use Deque over Stack?

JavaData StructuresStackDeque

.Net Data structures: ArrayList, List, HashTable, Dictionary, SortedList, SortedDictionary -- Speed, memory, and when to use each?

C#.Netvb.netArraysData Structures

What is the best way to implement nested dictionaries?

PythonData StructuresDictionaryMappingAutovivification

Why is std::map implemented as a red-black tree?

C++DictionaryData StructuresStlBinary Search-Tree

Array versus linked-list

ArraysData StructuresLinked ListLanguage Agnostic

Why do we use arrays instead of other data structures?

ArraysData Structures

How is set() implemented?

PythonData StructuresSetCpython

How are multi-dimensional arrays formatted in memory?

CArraysMemoryData StructuresStack Memory

Get keys from HashMap in Java

JavaData StructuresJava 6

How to print binary tree diagram in Java?

JavaData StructuresPrintingBinary Tree

How does the HyperLogLog algorithm work?

DatabaseAlgorithmMathData StructuresHyperloglog

What is the difference between Python's list methods append and extend?

PythonListData StructuresAppendExtend

Simplest code for array intersection in javascript

JavascriptData StructuresIntersection

How do you implement a Stack and a Queue in JavaScript?

JavascriptData StructuresStackQueue

How do I clear the std::queue efficiently?

C++Data StructuresStlQueue

What would a "frozen dict" be?

PythonDictionaryData StructuresImmutability

Are duplicate keys allowed in the definition of binary search trees?

Data StructuresComputer ScienceBinary Tree

Test whether a list contains a specific value in Clojure

Data StructuresClojure

Why would anyone use set instead of unordered_set?

C++AlgorithmData StructuresC++11

What are the lesser known but useful data structures?

Language AgnosticData StructuresComputer Science

lenses, fclabels, data-accessor - which library for structure access and mutation is better

Data StructuresHaskellRecordLenses

How to implement a Map with multiple keys?

JavaData Structures

How to merge YAML arrays?

ListData StructuresYaml

What's the difference between the data structure Tree and Graph?

SearchData StructuresMapTree

Get "Value" property in IGrouping

C#LinqData StructuresIgrouping

How would you implement an LRU cache in Java?

JavaCachingData StructuresLru

What is copy-on-write?

OptimizationDesign PatternsData StructuresCopy on-WriteProxy Pattern

HashMap get/put complexity

JavaData StructuresHashmapComplexity Theory

Calculate size of Object in Java

JavaMemoryMemory ManagementData Structures

How to avoid "too many parameters" problem in API design?

C#Data StructuresImmutability

How to check if a specific key is present in a hash or not?

RubyData StructuresAssociative Array

How to create the most compact mapping n → isprime(n) up to a limit N?

AlgorithmMathData StructuresPrimes

Why start an ArrayList with an initial capacity?

JavaData StructuresArraylistCapacity

How Do I Choose Between a Hash Table and a Trie (Prefix Tree)?

AlgorithmData StructuresHashtableTrie

Has anyone actually implemented a Fibonacci-Heap efficiently?

PerformanceAlgorithmLanguage AgnosticData StructuresFibonacci Heap

How do I instantiate a Queue object in java?

JavaData StructuresQueue

How to convert SQL Query result to PANDAS Data Structure?

PythonMysqlData StructuresPandas

Select Multiple Fields from List in Linq

C#LinqData Structures

Quick Way to Implement Dictionary in C

CData StructuresDictionary

Implement Stack using Two Queues

AlgorithmData StructuresStack

Red black tree over avl tree

AlgorithmData StructuresRed Black-Tree

When should I use the HashSet<T> type?

C#.NetData StructuresHashset

How do I represent a hextile/hex grid in memory?

Data Structures

Data structures for loaded dice?

AlgorithmLanguage AgnosticData StructuresRandomProbability

B-Tree vs Hash Table

MysqlData StructuresComputer ScienceComplexity TheoryB Tree

Are there strongly-typed collections in Objective-C?

Objective CGenericsData StructuresCollectionsStrong Typing

Representing graphs (data structure) in Python

PythonData StructuresGraph

What does it mean for a data structure to be "intrusive"?

C++CLanguage AgnosticData StructuresTerminology

How to implement a queue with three stacks?

AlgorithmData Structures

Given a string of a million numbers, return all repeating 3 digit numbers

PythonAlgorithmData StructuresNumber Theory

How do I create a Linked List Data Structure in Java?

JavaData StructuresLinked List

How to implement a binary tree?

PythonAlgorithmSearchData StructuresBinary Tree

When to use Preorder, Postorder, and Inorder Binary Search Tree Traversal strategies

Data StructuresComputer ScienceBinary TreePreorder

What is the advantage to using bloom filters?

AlgorithmData StructuresBloom Filter

Under what circumstances are linked lists useful?

Language AgnosticData StructuresLinked List

Are there any open source C libraries with common data structures?

CData Structures

Split a collection into `n` parts with LINQ?

C#.NetLinqData Structures

design a stack such that getMinimum( ) should be O(1)

AlgorithmLanguage AgnosticData StructuresStack

LinkedBlockingQueue vs ConcurrentLinkedQueue

JavaMultithreadingData StructuresConcurrencyQueue

How do I sort a list of dictionaries by a value of the dictionary?

PythonListSortingDictionaryData Structures

Does Java support structs?

JavaData Structures

Algorithm to find top 10 search terms

AlgorithmData Structures

Advantages of Binary Search Trees over Hash Tables

Data StructuresHashtableBinary Search-Tree

What's the best way of structuring data on firebase?

FirebaseData StructuresNosqlFirebase Realtime-Database

How to determine if binary tree is balanced?

JavaAlgorithmData StructuresBinary Tree

Time complexity of python set operations?

PythonData StructuresSetComplexity TheoryBig O

What is the difference between trie and radix trie data structures?

AlgorithmData StructuresTreePatricia TrieRadix Tree

Find kth smallest element in a binary search tree in Optimum way

AlgorithmData StructuresBinary TreeBinary Search

How to reverse a singly linked list using only two pointers?

CAlgorithmData StructuresLinked ListSingly Linked-List

How to implement a tree data-structure in Java?

JavaData StructuresTree

Check if two linked lists merge. If so, where?

AlgorithmLinked ListData Structures

When would I want to use a heap?

Data StructuresHeap

How does a hash table work?

Data StructuresHashHashtableModulo

Graph visualization library in JavaScript

JavascriptJqueryData StructuresGraph Layout

Reversing a linked list in Java, recursively

JavaData StructuresRecursionLinked List

How do I make and use a Queue in Objective-C?

Objective CCocoaData StructuresQueue

Data structure: insert, remove, contains, get random element, all at O(1)

Data Structures

Practical uses of different data structures

Data Structures

Why does Dijkstra's algorithm use decrease-key?

AlgorithmData StructuresPriority QueueGraph AlgorithmDijkstra

Hash table runtime complexity (insert, search and delete)

AlgorithmData StructuresHashTime ComplexityHashtable

What are the time complexities of various data structures?

JavaData StructuresTime Complexity

How to choose between map and unordered_map?

C++DictionaryData StructuresStlUnordered Map

Why can I define structures and classes within a function in C++?

C++Data StructuresFunctional Programming

Most efficient way to store thousand telephone numbers

AlgorithmData Structures

Is there any way to enforce typing on NSArray, NSMutableArray, etc.?

Objective CGenericsData StructuresCollectionsStrong Typing

How to detect a loop in a linked list?

JavaAlgorithmData StructuresLinked List

When is a ConcurrentSkipListSet useful?

JavaData StructuresCollectionsConcurrency

Reading a C/C++ data structure in C# from a byte array

C#.NetData StructuresMarshalling

Why is there no Tree<T> class in .NET?

C#.NetData Structures

Hashable, immutable

PythonData StructuresHashImmutability

What is the difference between a KD-tree and a R-tree?

Data StructuresKdtreeR Tree

Difference between xs and xsd in XML schema file?

XmlData StructuresXsd

Sorted array list in Java

JavaData StructuresSorted

How to implement a queue using two stacks?

AlgorithmData StructuresStackQueue

When to choose RB tree, B-Tree or AVL tree?

Data StructuresTreeB TreeAvl TreeRed Black-Tree

Algorithms based on number base systems?

AlgorithmMathData StructuresNumbersNumber Systems

Suffix tree and Tries. What is the difference?

AlgorithmData StructuresTrieSuffix Tree

Efficient (and well explained) implementation of a Quadtree for 2D collision detection

Data StructuresCollisionRectanglesQuadtree

When should I use a List vs a LinkedList

C#.Netvb.netData StructuresLinked List

Choice of programming language for learning data structures and algorithms

AlgorithmData StructuresLanguage Agnostic

Dynamically add data to a javascript map

JavascriptData StructuresMapsYui

Difference between "Complete binary tree", "strict binary tree","full binary Tree"?

Data StructuresTreeBinary Tree

How do I remove objects from an array in Java?

JavaArraysData StructuresData Manipulation

Split List into Sublists with LINQ

C#LinqData Structures

How to make heapq evaluate the heap off of a specific attribute?

PythonData StructuresHeap

What is the best way to combine two lists into a map (Java)?

JavaData StructuresCollections

What is the purpose of collections.ChainMap?

PythonPython 3.xDictionaryData StructuresCollections

Data structure for maintaining tabular data in memory?

PythonData Structures

LRU cache design

C++AlgorithmData StructuresLru

Linq - SelectMany Confusion

C#LinqData StructuresLinq to-Objects

Difference between red-black trees and AVL trees

Data StructuresTreeLanguage AgnosticAvl TreeRed Black-Tree

Objects vs arrays in Javascript for key/value pairs

JavascriptData Structures

What is the underlying data structure for Python lists?

PythonListData Structures

What is the fastest (to access) struct-like object in Python?

PythonPerformanceData Structures

Implement a queue in which push_rear(), pop_front() and get_min() are all constant time operations

AlgorithmData StructuresQueueBig O

How do you implement a circular buffer in C?

CData StructuresCircular Buffer

Why does the C++ STL not provide any "tree" containers?

C++Data StructuresTreeStl

Best implementation for Key Value Pair Data Structure?

C#Data StructuresCollections

Is using flexible array members in C bad practice?

CArraysData StructuresFlexible Array-Member

Algorithm for autocomplete?

AlgorithmAutocompleteScalabilityData StructuresAutosuggest

Difference between O(n) and O(log(n)) - which is better and what exactly is O(log(n))?

AlgorithmData StructuresComplexity TheoryBig OLogarithm

What's the difference between heapq and PriorityQueue in python?

PythonData StructuresHeapPriority Queue

Why are Fibonacci numbers significant in computer science?

AlgorithmMathData StructuresFibonacci

What is Python's heapq module?

PythonData StructuresHeapPython Module

Is there a more efficient implementation for a bidirectional map?

C++C++11Data StructuresMapBimap

JavaScript hashmap equivalent

JavascriptData StructuresLanguage FeaturesHashmap

Preserving order with LINQ

C#ArraysLinqSortingData Structures

Statistical performance of purely functional maps and sets

Data StructuresFunctional ProgrammingStatisticsAvl TreeRed Black-Tree

Storing 1 million phone numbers

AlgorithmData Structures

TreeMap or HashMap?

JavaData Structures

Designing a web crawler

Data StructuresSearch EngineWeb CrawlerGoogle SearchLarge Data-Volumes

Easiest way of using min priority queue with key update in C++

C++AlgorithmData Structures

Why should hash functions use a prime number modulus?

Language AgnosticData StructuresHash

What is the most efficient graph data structure in Python?

PythonPerformanceData StructuresGraph Theory

Looking for C++ STL-like vector class but using stack storage

C++Data StructuresStlVector

How are Python's Built In Dictionaries Implemented?

PythonData StructuresDictionary

Why is it better to have 100 functions operate on one data structure than 10 functions on 10 data structure

Data StructuresQuotations

Best data structure for implementing a dictionary?

StringAlgorithmDictionaryData Structures

python: deque vs list performance comparison

PythonPerformanceData StructuresBenchmarkingDeque

Does PHP have built-in data structures?

PhpData Structures

iterate vector, remove certain items as I go

C++Data StructuresVectorLoopsIterator

Why increase pointer by two while finding loop in linked list, why not 3,4,5?

AlgorithmData StructuresLinked ListCycleFloyd Cycle-Finding

Fastest data structure for contains() in Java?

JavaData StructuresSet

Why is Dictionary preferred over Hashtable in C#?

C#.Netvb.netData Structures

C# Data Structure Like Dictionary But Without A Value

C#.NetData Structures

Does java have a "LinkedConcurrentHashMap" data structure?

JavaData Structures

What is the difference between tree depth and height?

AlgorithmData StructuresTreeNodesTerminology

What's a RDF triple?

Data StructuresRdfXml NamespacesN Triples

B-tree faster than AVL or RedBlack-Tree?

AlgorithmData StructuresBinary Tree

Reverse the ordering of words in a string

AlgorithmData StructuresString

What is the most efficient way to sort an NSSet?

Objective CCocoaData StructuresSortingNsset

Linked List in SQL

SqlData Structures

How do you validate a binary search tree?

AlgorithmData StructuresBinary Search-Tree

Opposite of Bloom filter?

Data StructuresBloom Filter

Trie implementation

C++CData StructuresTrie

Difference between back tracking and dynamic programming

AlgorithmData Structures

How to keep an Javascript object/array ordered while also maintaining key lookups?

JavascriptData Structures

Is there any graph data structure implemented for C#

C#.NetData StructuresGraph Theory

What is the intuition behind the Fibonacci heap data structure?

Data StructuresFibonacci Heap

Difference between binary tree and binary search tree

Data StructuresTreeBinary TreeBinary Search-Tree

What do I use for a max-heap implementation in Python?

PythonData StructuresHeapRecursive Datastructures

The best way to calculate the height in a binary search tree? (balancing an AVL-tree)

AlgorithmData StructuresBinary TreeAvl TreeTree Balancing

How to check deque length in Python

PythonPython 3.xPython 2.7Data Structures

DAG vs. tree using Git?

GitData Structures

How would you represent a Rubik's Cube in code?

Data StructuresRubiks Cube

How to find nth element from the end of a singly linked list?

AlgorithmLinked ListData Structures

ArrayList Vs LinkedList

JavaData StructuresCollectionsArraylistLinked List

What's an appropriate search/retrieval method for a VERY long list of strings?

C#PerformanceData StructuresLookup

Difference between a HashMap and a dictionary ADT

JavaData Structures

How to make a dictionary that returns key for keys missing from the dictionary instead of raising KeyError?

PythonDictionaryData StructuresDictionary Missing

Interview: Remove Loop in linked list - Java

JavaData StructuresLinked List

Set of objects in javascript

JavascriptObjectData StructuresSet

How to Correctly Use Lists in R?

RListData StructuresLanguage FeaturesAbstract Data-Type

Haskell's algebraic data types

Data StructuresHaskellTypesFunctional ProgrammingAlgebraic Data-Types

Why do we need Deque data structures in the real world?

Data StructuresDeque

Javascript data structures library

AlgorithmData StructuresJavascript

Array-Based vs List-Based Stacks and Queues

ArraysData StructuresStackQueueLinked List

what is the difference between set and unordered_set in C++?

C++AlgorithmData StructuresC++11

Visual C++ equivalent of GCC's __attribute__ ((__packed__))

C++CVisual C++GccData Structures

What are the underlying data structures used for Redis?

AlgorithmData StructuresRedis

What is the true difference between a dictionary and a hash table?

PythonData StructuresHashDictionaryHashtable

Chained Hash Tables vs. Open-Addressed Hash Tables

Data StructuresHashtable

Type-safe generic data structures in plain-old C?

CGenericsData StructuresCode Generation

How to create a 2 way map in java

JavaData Structures

What is the benefit of purely functional data structure?

Data StructuresHaskellFunctional ProgrammingOcamlPurely Functional

Hash : How does it work internally?

JavaAlgorithmData StructuresHash

Interview question: data structure to set all values in O(1)

Data Structures

Difference between tuples and frozensets in Python

PythonData StructuresSetTuples

In Python, when to use a Dictionary, List or Set?

PythonListDictionaryData StructuresSet

How can CopyOnWriteArrayList be thread-safe?

JavaData StructuresConcurrencyJava Memory-Model

What are the differences between B trees and B+ trees?

DatabaseData Structures

Converting YAML file to python dict

PythonData StructuresDictionaryYaml

Performance differences... so dramatic?

C#.NetData StructuresCollections

Firebase data structure and url

Data StructuresNosqlFirebase

what is "stack alignment"?

C++Data StructuresMingwVisual C++Compiler Construction

How does a sentinel node offer benefits over NULL?

C++AlgorithmData Structures

What is C# analog of C++ std::pair?

C#.NetData StructuresStd PairBase Class-Library

List of all unique characters in a string?

PythonPerformanceData Structures

Is it possible to query a tree structure table in MySQL in a single query, to any depth?

MysqlSqlDatabase DesignData StructuresHierarchical Data

Repository pattern vs. "smart" business objects

Data StructuresArchitectureRepository Pattern

Why use SQL database?

SqlDatabaseDatabase DesignData Structures

How to delete in a heap data structure?

AlgorithmData StructuresHeap

Is Minimum Spanning Tree afraid of negative weights?

AlgorithmData StructuresGraphMinimum Spanning-Tree