T20DSAChallenge by Bilal Ashiq

Solved 8 DSA problems in 7 days using Prefix Sum & Range Queries with optimized, clean code — aiming for top performance, MAANG referrals, and expert-level mastery.

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Inspiration

As a passionate Computer Science student, I joined the T20DSAChallenge to master Range Queries & Prefix Sum, which are fundamental in solving real-world problems efficiently. The opportunity to gain referrals and mentorship with MAANG companies inspired me to participate and give my best every day.

What it does

This submission showcases my daily problem-solving journey in the challenge. Each solution focuses on implementing optimized prefix sum/range query algorithms that improve time and space complexity.

Each day tackles a different problem using techniques like:

  • 1D/2D prefix sums
  • Binary Indexed Trees (Fenwick Trees)
  • Sliding window optimizations
  • Offline queries

How we built it

  • Language: C++ (optimized with STL) / Python (for readability)
  • IDE: VS Code, GeeksforGeeks IDE
  • Version control: GitHub repository for code & explanation
  • Tools: Markdown for documentation, Codeforces-style testing

Challenges we ran into

  • Understanding edge cases with large input sizes
  • Optimizing time complexity to prevent TLE
  • Managing daily deadlines alongside other academic tasks
  • Making reusable prefix sum logic across different problem types

Accomplishments that we're proud of

  • Completed all problems on time
  • Wrote optimized solutions with full test case coverage
  • Maintained a clean GitHub repo with explanations
  • Understood advanced range query patterns deeply in just 7 days!

What we learned

  • Deep understanding of prefix sums in 1D and 2D
  • How to structure solutions for range sum, min, max queries
  • Efficient data structure choices under constraints
  • How to balance readability with performance in competitive code

🔮 What's next for Bilal Ashiq DSA

  • Continue solving advanced DSA topics like Segment Trees & Mo’s Algorithm
  • Create a public GitHub repository as a full Prefix Sum Mastery Guide
  • Make YouTube tutorials for fellow beginners
  • Aim for top ranks in Codeforces & LeetCode contests
  • Apply for mentorship opportunities unlocked by this challenge

Let me know if you'd like a Markdown-ready GitHub README, an auto-submission script, or help writing explanations for each day’s problem.

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