HashMap
A HashMap is a data structure that stores key-value pairs using hashing for fast access, insertion and deletion. Keys are unique and each maps to exactly one value. It offers average O(1) time complexity for basic operations and is widely used for efficient lookups, caching and data mapping in applications.
Top HashMap Blogs
How to Find the Right View of a Binary Tree
Learn how to find the right view of a binary tree using DFS and BFS, with examples, code, complexity analysis and coding interview tips.
Left View of a Binary Tree: DFS and BFS Approaches Explained
Learn how to find the left view of a binary tree using DFS and BFS, with examples, code, complexity analysis, common mistakes and interview tips.
Top View of a Binary Tree Using BFS and DFS | Complete Guide
Learn how to find the top view of a binary tree using DFS and BFS with step-by-step explanations, examples, code, complexity analysis and interview insights.
Bottom View of a Binary Tree: DFS vs BFS Approach
Learn to find the bottom view of a binary tree using horizontal distance. Compares a buggy DFS attempt, a fixed DFS and the optimal BFS solution in Java.
Longest Playlist With No Repeated Songs : Brute Force to Optimal
Find the longest playlist with no repeated songs using brute force, HashSet, and HashMap sliding window techniques, with Java code and dry runs.
What Happens If You Override Equals() but Not GetHashCode() in C#
Top HashMap Articles
Amazon Transaction Logs
Amazon Transaction Logs (example question), Amazon Transaction Logs Interview question
Popular Topics
C#Low-Level Design (LLD)Coding ProblemsInterview ExperienceInterview QuestionsHigh-Level Design (HLD)ArrayDatabaseSQLMethod
C# (C-Sharp) is a modern, object-oriented programming language developed by Microsoft for building secure, scalable applications. It runs on the .NET platform and supports features like strong typing, garbage collection, LINQ, async programming and cross-platform development. C# is widely used for web, desktop, game development (Unity), cloud services and enterprise-level software solutions.
Low-Level Design (LLD) defines the internal workings of individual software components. It focuses on class structures, object interactions, methods and data flow. LLD translates high-level architecture into detailed designs using principles like SOLID and design patterns, serving as a blueprint for developers to write clean, maintainable and scalable code.
Coding problems are exercises designed to test a programmer’s ability to write logic, solve challenges and apply algorithms or data structures. They help improve problem-solving skills, logical thinking and coding efficiency. Common in interviews and competitive programming, coding problems range from simple tasks to complex algorithmic challenges, preparing developers for real-world software development scenarios.
An interview experience is a detailed account of the interview process for a specific role, covering rounds, questions asked, difficulty level, preparation tips and personal insights to help future candidates understand what to expect and how to prepare effectively.
Interview Questions are structured queries asked by employers to evaluate a candidate’s technical skills, problem-solving ability, experience, communication skills and cultural fit. These questions can include HR, behavioral, technical, coding and situational topics to assess whether the candidate is suitable for the job role and organization.
High-Level Design (HLD) outlines the system architecture and overall structure of a software solution. It defines components, modules, data flow, technologies and their interactions. HLD focuses on scalability, performance and reliability, serving as a bridge between requirements and Low-Level Design. It’s essential for planning system-wide decisions.
An array is a linear data structure that stores multiple elements of the same type in contiguous memory locations. It allows fast access using index positions, making operations like retrieval efficient. Arrays are widely used for organizing data, implementing algorithms and building other data structures. However, their size is fixed, making resizing difficult compared to dynamic collections.
A database is an organized collection of data. It is the collection of schemas, tables, queries, reports, views, and other objects. The data are typically organized to model aspects of reality in a way that supports processes requiring information. Use this tag if you have questions about designing a database.
SQL stands for Structured query language. It is a programming language for storing and processing information in a relational database. It is standard language for accessing and manipulating databases.
A method is a block of code that performs a task.
Popular Articles
how to install docker on amazon ec2 instance. docker installation command on linux machine, docker commands, Commonly Used Docker Commands on EC2
Mastering the Singleton Design Pattern in C#, Singleton Design Pattern in Depth: Structure, Use Cases and Best Practices, in depth design pattern, LLD , low level design
List Handling in Java vs C# vs C++ A Deep Comparison, This comparison provides a full view java , c# and c++ List like data structures
Top High-Level Design(HLD) Interview Questions and answers, HLD QnA, HLD interview preparation
Maximum Product Subarray, Find Maximum Product Subarray in an Array, Given an integer array arr, find a subarray that has the largest product,
Top 50 SQL Interview Questions and Answers (Beginner to Intermediate). Top SQL Interview Questions for fresher. Frequently asked SQL interview questions with answers
Learn how to create a primary key in SQL using syntax and examples. Ensure unique records, improve query performance and build table relationships.
install mysql by docker. docker mysql server installation. MySQL is one of the most popular open-source relational database management systems. Docker container is a great way to manage and deploy databases in a portable and isolated environment. In this article, we will walk through the steps by step to install and run MySQL in Docker.
You are given two integer arrays arr1 and arr2, sorted in accending order, and two integers m and n, representing the number of elements in arr1 and arr2 respectively. Merge arr1 and arr2 into a single array sorted in accending order.
Most Popular Tools
Explore our top online tools including a blank page for notes, a QR code generator, word counter and collaborative editor. These free, easy-to-use utilities help you write, analyze, share and organize content faster. Perfect for developers, creators and students to streamline everyday digital tasks efficiently.
Blank Page
Create a blank canvas for your ideas, notes or sketches. Use this tool for rough work and jotting down your thoughts
QR Code Generator
A QR Code Generator is a tool that instantly converts text, URLs or other data into a scannable QR code. Users can create custom QR codes for websites, contact info or messages. It's commonly used for quick access, sharing and printing without needing a backend or complex setup.
Word Counter
Perform various string operations like counting characters, words or letters.
Collaborative Editor
Collab Editor is a powerful, free-to-use online platform that lets you collaborate in real-time. Whether you re working on documents, brainstorming idea, or discussing projects etc