Advanced Exercises

Use these after ordinary editor reps when you want to practice reading unfamiliar code, finding operational risks, or decomposing an open-ended system. They supplement the Practice Drills; they do not replace the comments, code, and tests loop.

Code reading

The Python files are intentionally buggy or inefficient. For each exercise:

1. Read signatures and docstrings.
2. Trace one execution path.
3. Test empty, large, malformed, and concurrent inputs where relevant.
4. Estimate the time and space cost of the hot path.
5. Propose two or three fixes, ordered by impact.

Exercise	File	Focus
Caching Service	src/practice/code_reading/ex01_caching_service.py	eviction, thread safety
Flight Data Pipeline	src/practice/code_reading/ex02_flight_data_pipeline.py	streaming, batching, failures
Rate Limiter	src/practice/code_reading/ex03_rate_limiter.py	token buckets, windows, concurrency

Check for unbounded memory, nested work on the hot path, missing validation, shared mutable state, blocking I/O, and calls inside loops. Explain the impact before proposing a change.

Problem decomposition

The open-ended prompts train scope, interfaces, tradeoffs, and test strategy.

Exercise	File	Focus
Vehicle Tracking	src/practice/decomposition/ex02_vehicle_tracking.md	geospatial indexing, live updates

State assumptions, split the system into parts, identify the riskiest seam, and describe how you would verify it. An untimed conversational rep works well for a first pass; use an observed mock when concise narration is the target.

For a longer scheduled block, run just practice-day 12 and follow the printed stop conditions. Use the daily conductor only when you intend to run the full block.