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Welcome to Questions100

Questions100 is your comprehensive guide to mastering the most frequently asked coding interview questions. This collection includes 100 carefully curated problems covering AI, Machine Learning, and Cybersecurity topics, complete with detailed solutions, complexity analysis, and practical applications.

What You’ll Find Here

100 Curated Problems

High-frequency interview questions organized by category and difficulty

17 Problem Categories

From Arrays and Trees to Dynamic Programming and Graphs

Detailed Solutions

Python implementations with time/space complexity analysis

Real-World Applications

See how these algorithms apply to production systems

Key Features

Each problem includes:
  • Complete problem description with constraints
  • Multiple test cases with explanations
  • Optimal Python solution with comments
  • Time and space complexity analysis
  • Alternative approaches when applicable
Every problem connects to practical applications:
  • Named systems and platforms (AWS, PostgreSQL, Redis)
  • Specific security tools (Snort, Splunk, Wireshark)
  • Production use cases and scenarios
Prepare effectively with:
  • Study plans organized by week
  • Common pitfalls and edge cases
  • Interview tips and strategies
  • Frequency ratings for prioritization
Explore problems through:
  • 3D graph visualization of problem relationships
  • Category-based browsing interface
  • Search and filter capabilities

Problem Statistics

21 Easy

Foundation-building problems

63 Medium

Core interview challenges

16 Hard

Advanced problem-solving

Quick Start

1

Choose Your Path

Start with study plans for structured learning, or dive into problem categories to focus on specific topics.
2

Understand the Problem

Read the problem description, constraints, and examples carefully before attempting a solution.
3

Analyze & Solve

Study the optimal solution, understand the complexity analysis, and implement it yourself.
4

Practice

Work through related problems in the same category to recognize patterns and build intuition.

Array & Hashing

Two Sum, Subarray Sum, Hash Map patterns

Trees & BST

Binary Tree, BST, Tree Traversal problems

Dynamic Programming

Optimal substructure and memoization

Graphs & DFS/BFS

Graph traversal and shortest path algorithms

Why Questions100?

This resource was created to bridge the gap between theoretical algorithm knowledge and practical interview preparation. Each problem has been carefully selected based on interview frequency data and enhanced with real-world context to help you understand not just how to solve problems, but why these patterns matter in production systems.

Ready to Begin?

Start with Quickstart

Get oriented with the most important problems

Browse All Problems

Explore the complete problem set

Source Repository: sparktsao/Questions100 Happy Learning! 🚀

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