Day 8 of the SDESheetChallenge by takeUforward completed! Smashed 4 core SDE sheet problems and the daily LeetCode challenge.
Mastered Count Subarrays with Given XOR K (Medium) using the prefix XOR and hash map frequency tracker. By leveraging the XOR property P[j]=P[i]⊕K, the algorithm counts matching subarrays in O(N) time.
Solved Longest Substring Without Repeating Characters (Medium) using the sliding window pattern and Create Binary Tree From Descriptions (Medium) using a parent-child hash map structure to reconstruct the tree and locate the root node.
Studied FB News Feed system design, analyzing the fundamental tradeoffs between Fanout-on-Read (pull model, heavy read query load) and Fanout-on-Write (push model, write amplification). Explored the Hybrid Model (precomputing feed for normal users, dynamically fetching celebrity posts on read) and cache replication strategies to resolve hotkey bottlenecks.