Скачать или смотреть LeetCode 2563 | Count Fair Pairs | Divide & Conquer | O(n(logn)^2) solution | MAANG Prep

LeetCode 2563 | Count Fair Pairs | Divide & Conquer | O(n(logn)^2) solution | MAANG Prep

Welcome to Pen and Paper! In this video, we solve LeetCode 2563 – Count the Number of Fair Pairs using a divide & conquer / recursive strategy (instead of the more common two-pointer / binary search) — a novel twist you’ll want to see.

🔍 What you’ll learn:

Problem statement & constraints

Why a naive O(n²) fails for large inputs

How to design a divide & conquer / merge-like approach to count the fair pairs in O(n log n)

Step-by-step walkthrough, recursion + merging logic, and correctness proof

Edge cases, pitfalls, optimizations

🏢 Companies & places this problem is asked / relevant for:
This kind of pair-sum / range counting problem is relevant in interviews at Amazon, Microsoft, Google, Meta, Apple, Flipkart and other companies that test advanced algorithm + counting / pair logic.

✅ If you are preparing for coding interviews, this video will help you understand a powerful pattern (divide & conquer + counting) that generalizes beyond this problem.

📌 For more curated problems, full solutions & notes, visit penpaperpreparation.com

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🚀 Let’s go: solve LeetCode 2563 with divide & conquer 💡