LeetCode: Unique number of occurrences LeetCode: Find the Difference of Two Arrays Clean Architecture: Chapter 15 Architecture

• LeetCode: Unique number of occurences - I speculated that Set is better than O(nlogn)
• LeetCode: Find the Difference of two arrays - Someone took advantages of good null case handling for Set delete method. I learnt that language specific knowledge is somewhat of an advantage
• Clean Architecture - Finish chapter 15