DSA: Data Structures & Algorithms Reference

A practical, code-driven guide to mastering Data Structures and Algorithms for interviews, competitive programming, and real-world engineering. This repository features clean Python implementations, concise notes, and curated problem patterns for each topic.

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Repository Structure

• DSA_Intro/ — Foundations, arrays, and core concepts
• Arrays/, LinkedLists/, Queues/, Trees/, Heaps/, Hashing/, Sorting/, Recursion/, Graphs/ — Each topic contains:
  • notes.md: Theory, patterns, and interview tips
  • *.py: Idiomatic Python implementations and sample problems
• Low-Level-Design/ — OOP and design patterns for system design interviews
• Python/ — Pythonic DSA idioms and best practices
• assets/ — Visuals and diagrams

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Folder Guide

• DSA_Intro/ — Quickstart and foundational DSA concepts.
• Arrays/ — Array operations, patterns, and interview problems.
• LinkedLists/ — Singly, doubly, and circular linked list implementations and tricks.
• Queues/ — Queue types, patterns, and real-world use cases.
• Trees/ — Binary trees, BSTs, traversals, and tree algorithms.
• Heaps/ — Min/max heaps, heap operations, and heap-based problems.
• Hashing/ — Hash tables, collision resolution, and hashing patterns.
• Sorting/ — Classic sorting algorithms and searching techniques.
• Recursion/ — Recursion patterns, backtracking, and practice problems.
• Graphs/ — Graph representations, BFS/DFS, and graph algorithms.
• Low-Level-Design/ — OOP and design patterns for system design interviews.
• Python/ — Pythonic DSA idioms, tips, and best practices.
• assets/ — Visual diagrams and supporting images.

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Getting Started

1. Clone the repository:

   git clone https://github.com/yourusername/DSA.git
   cd DSA
   

2. Explore by topic:

   • Read notes.md in each folder for theory and interview patterns
   • Run and modify *.py files for hands-on practice

3. Use the curated LeetCode/interview problem lists in each notes file for targeted practice.

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Sample Usage

from Heaps.heaps import MinHeap
h = MinHeap()
h.insert(5)
h.insert(2)
h.insert(8)
print(h.extract_min())  # 2

from Graphs.graphs import Graph
G = Graph(5)
G.add_edge(0, 1)
G.add_edge(1, 2)
print(G.bfs(0))

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Navigation

• Start with notes.md for theory and patterns
• Dive into Python files for implementation details
• Use problem lists for focused LeetCode prep
• See Low-Level-Design/ for design/system rounds
• See Python/pythonic_notes.md for Python-specific tips

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Topics Covered

• Arrays, Linked Lists, Stacks, Queues, Trees, BSTs, Heaps, Hashing, Sorting, Graphs, Recursion, LLD, and more
• Each topic: Clean code, edge cases, patterns, and real-world applications

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Contributing

Pull requests and suggestions are welcome. Open an issue or submit a PR.

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License

MIT

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Ace your interviews. Master the patterns. Write clean code.