DS Lab: Sorting & Selection Activities Solutions in Java | Kth Smallest, Max Difference, Pairs Sum

📌 Java Data Structures Lab – Sorting & Selection Activities (Solutions Video) In this video, I solve and explain the main practice activities from the Sorting & Selection Algorithms module step by step using Java. The focus is on applying sorting as a tool to solve classic array problems efficiently and correctly. ✅ Activities Solved in This Video 1️⃣ Find the k-th smallest element - Using sorting to simplify selection - Understanding indexing after sorting 2️⃣ Find the maximum difference in an array - Tracking minimum values - Interpreting the result as (maxDiff, firstElement, secondElement) 3️⃣ Find all pairs with sum = target - Sorting + two-pointer technique - Efficient alternative to brute force 4️⃣ Find the missing number - Sorting-based logic - Detecting gaps in a sequence 🧠 Key Concepts Reinforced - Using Merge Sort as a helper algorithm - Applying two-pointer techniques - Time complexity analysis after sorting - Translating problem statements into clean, structured code - Writing readable and testable Java methods 💻 Reference Materials - Lecture & activities repository: https://github.com/Maryam-Skaik/java-ds-lab-sorting - Source code demonstrated in this video is aligned with the activities folder in the repository. ▶ Instructions for Students - Watch the full video carefully before reviewing the code. - Try to solve each problem on your own first. - Compare your solution logic with the explained approach. - Focus on why sorting helps, not only on the final answer. - Practice with different inputs (duplicates, edge cases, small arrays). 🎓 This video is part of the Data Structures Lab – Sorting & Selection Module and serves as a guided solutions walkthrough to strengthen your algorithmic thinking and exam readiness.