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A-Level Computer Science 9618 Paper 2: Algorithms, Code and Tracing
Computer science: algorithms and code
This paper tests problem solving in code: read a scenario, write the algorithm, write the program, then trace the output. Marks sit in structure – declarations, loop bounds, conditions, output format – each scored separately, so a clever answer with no declarations still loses marks.
How is A-Level Computer Science 9618 Paper 2 assessed, and what does each part carry?
Paper 2 (Problem-solving and Programming): Answered in pseudocode, 75 marks (25% A-Level); Paper 1 (Theory): Theory questions, 75 marks (25% A-Level)
Assessment at a glance (2027)
| Component | Content | Weighting | Duration |
|---|---|---|---|
| Paper 2 (Problem-solving and Programming) | Answered in pseudocode, 75 marks | 25% A-Level | 2 hours |
| Paper 1 (Theory) | Theory questions, 75 marks | 25% A-Level | 1 h 30 min |
A-Level Computer Science Paper 2 drilling technique: initialise variables; check loop bounds (0 TO n-1); state the precondition for search (binary needs sorted data); recursion needs a base case. Indent pseudocode to show structure.
What each paper is actually testing
| Paper | Drill focus | How marks are lost |
|---|---|---|
| Paper 2 (Problem-solving and Programming) | algorithms, data structures, programming | Variables are used without declaration or with the wrong data type, so the declaration marks go even when the logic is right. |
| Paper 1 (Theory) | hardware, software, data representation | An off-by-one loop bound corrupts the trace table, and every later mark falls with it. |
What is each A-Level Computer Science 9618 Paper 2 paper really testing, and what should you drill?
Paper 2 (Problem-solving and Programming): algorithms, data structures, programming; Paper 1 (Theory): hardware, software, data representation
Drill order: by topic, then by year, then the mark scheme
| Step | What you do | Why |
|---|---|---|
| 1. By topic | Work through each topic, starting with the paper that allows least help (no calculator / closed book) | Exposes what is genuinely not understood |
| 2. By year | Whole papers to time, one or two a week | Trains pace, stamina and question selection |
| 3. Mark scheme | Go through the marking scheme question by question and log the scoring steps you missed | Most lost marks are written wrong, not thought wrong |
Should drilling go by topic first or by year?
By topic first, then whole papers by year, then the mark scheme. The first third of the time goes topic by topic (8-10 years of the same topic back to back), the middle switches to timed whole papers, and the last fortnight only redoes the recurring errors from your log.
A 12-week drilling timetable
| Week | Phase | What to do |
|---|---|---|
| Weeks 1-3 | By topic: foundation | Topic by topic, starting with the easiest marks, building habits and recall |
| Weeks 4-6 | By topic: core | 8-10 years of the same topic back to back, errors classified by topic |
| Weeks 7-8 | By topic: advanced and electives | Elective and higher-order topics, now under time pressure |
| Weeks 9-10 | By year: timed papers | One full paper a week, timed, no reference materials |
| Week 11 | Mark scheme work | Question by question against the marking scheme; list the scoring steps you omitted |
| Week 12 | Plug holes and simulate | Only the recurring errors from your log, then one full exam simulation |
Subject-specific weighting for this timetable: Weeks 1-3: algorithms and declarations. Pseudo-steps as comments, then declarations, then the body; mark declarations first when you review.
Weeks 4-6: loops and conditions. Dry-run each program three times – empty, one item, many – and fix any bound error immediately.
Weeks 7-9: trace tables and testing, tracing line by line and adding normal, boundary and erroneous test data.
Weeks 10-12: full papers to time, structure before detail.
Use it properly: this is not a checklist to finish. Every week must keep time for redoing errors, or from week 9 you will be repeating the same batch.
Pacing
| Paper | Time | Suggested split |
|---|---|---|
| Paper 2 (Problem-solving and Programming) | 2 hours | about 20 min per question |
| Paper 1 (Theory) | 1 h 30 min | about 12 min per question |
How should the time be split inside each A-Level Computer Science 9618 Paper 2 paper?
Paper 2 (Problem-solving and Programming): about 20 min per question; Paper 1 (Theory): about 12 min per question
The drilling mistakes that cost the most marks
| Mistake | What it looks like | What actually happens | Instead |
|---|---|---|---|
| Uninitialised variable | Total added directly | Set Total <- 0 first | Total <- 0 |
| Wrong loop bounds | 1 TO 5 | 0-based array: 0 TO 4 | 0 TO 4 |
| Binary search precondition | Binary on the fly | Data must be sorted | sorted data |
The error log and the mark scheme
Three columns: the code as written, the scheme key words (declaration, type, bound, condition, output, test), and which was missing. Put the most frequent gap on the first page of your notes.
How many years should you drill?
9618 replaced the older 9608, and earlier papers use different conventions: build the answer structure on three to five years of current papers, then use the official specimen and textbook exercises where years are thin.
How many years of past papers is enough?
9618 replaced the older 9608, and earlier papers use different conventions: build the answer structure on three to five years of current papers, then use the official specimen and textbook exercises where years are thin.
Frequently asked questions
Is this page a mock paper or a drilling guide?
This is the A-Level Computer Science 9618 Paper 2 drilling guide: assessment structure, drill order, a 12-week timetable, pacing, common mark losses and the error-log method. For questions with answers, use the A-Level Computer Science 9618 Paper 2 mock papers linked under Related.
By topic or by year first?
By topic. Eight to ten years of the same topic back to back is what exposes repeating errors; going straight to whole papers just repeats the same batch under time pressure.
How should the error log be written?
Do not copy out questions. Per error record four things: question reference, which step failed (concept, wording, calculation), what the mark scheme requires, and the correct action next time.
Does a more elaborate solution earn more marks?
No, and it adds failure points. The scheme only rewards the structure it asked for, so plain steps with declarations and conditions beat showmanship.
Must the trace table run to the last line?
Yes, to the end of the program or the line the question names; skipping rows invalidates everything after. Number the iterations first, then fill one row at a time.
Official references
| Resource | What to use it for |
|---|---|
| Cambridge A-Level Computer Science 9618 syllabus (2027-2029) | Confirm the Paper 1-4 marks and times |
| https://www.tutorzone.com.hk/en-alevel-computer-science-9618-paper-1-mock-2027/ | A-Level Computer Science Paper 1 drilling mock |
Related: practice area · A-Level Computer Science Paper 1 drilling mock
Next step: find a tutor / register as a tutor
After drilling, the hard part is telling a conceptual error from a writing error. Tell us the year group, the school and your available times, and TutorZone will match you with a tutor who knows the HKEAA assessment requirements.
Demand for tutors in this subject is steady, and those who can explain the marking scheme and where marks are won are especially sought after. Register free; you pay only when a match succeeds.
