Day27
60-day SSE plan
Tic Tac Toe • Distributed Cache (Redis-like) • Union-Find • Tech: Concurrency & Multithreading
Algorithm
DSA
Union-Find — Redundant Connection (LC 684)
Find the extra edge that creates a cycle in an undirected graph.
Example
Input: edges forming a cycle → Output: the extra edge
Where it shows up
Cycle detection, connectivity in networks, Kruskal pre-checks.
References
Low-level design
LLD
Tic Tac Toe
Requirements
- Design 3x3 game; win/draw detection; replay.
Expectations
- Classes for Board, Player, Game; strategy for winner check.
- Unit tests for edge cases.
Where it shows up
Turn-based game engines, board game modeling.
References
High-level design
HLD
Distributed Cache (Redis-like)
Requirements
- SET/GET/DEL, TTL; sharding; replication; eviction policies.
Expectations
- Consistent hashing, leader election, cache-aside/write-through.
- Failure handling & split-brain prevention.
Where it shows up
Backend acceleration, DB offload, low latency reads.
References
Today's deep-dive
Tech
Concurrency & Multithreading
Build a bounded thread pool demo; compare synchronized vs ReentrantLock; show visibility with volatile.
Where it shows up
Building scalable chat/messaging platforms, real-time collaboration tools, and distributed systems requiring concurrency control.