PlacementPilot Spring AI + pgvector, Java Internals, A2Z Pattern Coverage, DDIA, Mock 9

Interview-weight string algorithms only: KMP Algorithm (Knuth-Morris-Pratt string matching) via the LPS array (LC #28, LC #1392 Longest Happy Prefix), Rabin-Karp polynomial rolling hash (LC #187 Repeated DNA Sequences), Z-algorithm (concept only, 20 min), Shortest Palindrome (min characters to add at front, LC #214). A2Z pattern coverage (representative problems) completed across all 18 steps. TUF+ A2Z Step 18

Solve 4 new problems from NeetCode 150 — Math & Geometry (matrix problems); time-box each at 25 min before any hint (2.5h includes editorial on misses), then log pattern and miss reason in the Journal. Never repeat a problem already in the ledger.

Codeforces Div.2/3 (fortnightly) + LeetCode Weekly Contest + mandatory upsolving. Ratings are tracked metrics, never gates.

Extend the PlacementPilot service built since W16 with Spring AI 2.0 (requires Boot 4.x) and PostgreSQL pgvector: PDF document reader, semantic chunking, token estimation and embedding ingestion; reuse the Redis cache from W26. Architecture §6.1

Implement cosine similarity vector search, top-k retrieval with metadata filtering (e.g. filter placement resources by company/difficulty), prompt template engineering, and multi-turn chat memory in Spring AI. Architecture §6.1

Under a strict 45-minute timer, design a distributed chat system (WhatsApp/Slack-style): functional/non-functional requirements, API design, message storage, real-time delivery (WebSockets vs long polling), presence service, read receipts, group chats. Architecture §6.2

Kleppmann & Riccomini Designing Data-Intensive Applications (2nd ed., 2026 — go by topic), replication and sharding chapters: leader-follower replication, replication lag anomalies (read-after-write, monotonic reads), hash vs range partitioning, secondary index partitioning. Architecture §6.2

Calendar check against the Opportunity Calendar (Architecture §16); send ≥ 8 personalised outreach messages (alumni, seniors, recruiters) and log each in the Tracker; follow up open threads; ask for a referral 1–2 days after any OA invite; apply within 72 h of any new posting on the Target-40.

60-min round on an unfamiliar small repo: extend one feature and add tests with an AI assistant while narrating; reject at least one wrong suggestion explicitly. Rubric: AI-assisted round (Architecture §15.6: problem framing, verification, tests, narration).

Take an unfamiliar small repo, extend one feature and add tests with an AI assistant while narrating; practise verifying or rejecting AI output and prepare an honest "how I use AI at work" talking point. Zero-AI wording applies only to timed DSA sets. Rubric: AI-assisted round (Architecture §15.6: problem framing, verification, tests, narration).

Read an unfamiliar 150-line Java class, find 3 seeded bugs without running it, then fix them with tests while narrating.

25-minute timed mixed set (quant, logical reasoning, data interpretation) from IndiaBix / PrepInsta-style banks; log accuracy and seconds per question in the Tracker. Target: hold ≥ 70% accuracy.

Timed 45 min using the LLD rubric (Architecture §15): requirements → entities → interfaces → patterns → concurrency → tests → extensibility. Write the checklist and a one-page class diagram; self-timed [VERIFY lldcoding.com / Workat.tech availability]. Problem: in-process rate limiter with pluggable algorithms (token bucket, sliding window) behind a Strategy interface; concurrency: atomic counters under contention.

Deeper review of W23 JVM Memory & GC plus classloaders, String pool immutability, equals() and hashCode() contract, exception hierarchy, Java 21 features. Architecture §6.5 Absorbs the W23 JVM Memory & GC topics (heap regions, G1/ZGC, GC roots, memory leaks).