cs-105 — The Room Booking Audit
| Field | Value |
|---|---|
| id | cs-105 |
| difficulty | Beginner |
| topics | cleaning, validation |
| lecture | lecture-27 |
| estimated time | 5-minute attempt + 10-minute discussion |
| prerequisites | none |
| objective | state inputs, outputs, and assumptions, then solve a small instance by hand |
| solution | held by the instructor; discussed after the attempt |
Problem
Booking rows with missing rooms, end-before-start times, and double bookings. Define rules, count violations, decide repairs vs flags.
Your deliverable is the stated assumptions, the booking rule made precise enough to implement, and one borderline record with your verdict and why. If the problem is ambiguous anywhere, state the assumption you are making and carry on — a stated assumption is part of a good answer.
Examples
- Input: rows: (room=NULL, 9-10), (B12, 10-9 end<start), (B12, 13-14) twice (double), (B14, 9-10)
- Output: 3 violations: missing room, inverted time, duplicate booking; repairs flagged not silent
Solve for the worked instance first. Then ask what would change if one number, name, or condition were replaced by something stranger.
What to notice
- Rule table first: rule, violation count, repair or flag. Silent dropping is never a policy.
- Writing the rules IS the solution; code is transcription.
- Every assumption is a place where two good answers can differ.
Discussion starter
After the solution is revealed, the class spends five minutes on this prompt: "Propose one extra rule that would change the verdict — is it an improvement?"
Constraints and assumptions
- Difficulty: Beginner (no prior experience assumed).
- Topics: cleaning, validation.
- Classroom-scale inputs unless the problem says otherwise.
- Time-box: about five minutes for a first attempt; partial answers with clear reasoning are worth more than silent struggling.
- Optional stretch (not required): describe an alternative approach and say when it beats the obvious one.
Hints and extension
- First nudge: identify the pattern the worked instance uses before computing anything.
- If stuck after three minutes, write the input/output line you expect and trace the smallest example by hand.
- After the reveal, attempt the extension below before the next lecture.
- Extension challenge: Draft the audit trail paragraph a reviewer would need to trust your cleaning.