9618Paper 2 · Fundamental Problem-solving and Programming Skills§9.1, §9.2

9. Algorithm Design and Problem-Solving

Computational thinking (abstraction, decomposition), identifier tables, pseudocode with the three basic constructs, structured English and flowcharts (and converting between them), stepwise refinement and logic statements.

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Statometer46RegularNext Paper 269%

Marks a paper8.9 · 12%Rank#11 of 12 · #3 on P2Trend · last 12↘Full stats

Everything for this topic — study hub

AS Level · 9618 · Paper 2

Statometer — what 33 real papers say about this topic and each of its 3 syllabus bullets

Regular · #11 of 12 in AS Level · recomputed with every new session

Regular#11 of 12 in AS Level#3 on Paper 2↘ Easing

Comes up most sessions for a few marks — know the definitions and one worked example.

Next Paper 2: 69%; 7 in 10 chance it is set
Marks a paper: 8.9 / 75; 12% of Paper 2 · fair share 25%
Appeared in: 23 / 33; Paper 2 sittings 2021–2026
Last set: May/Jun 2026; 9618/23 · Q4 · 4 marks · 11-series streak

Marks in each of the last 12 Paper 2 sittingsOct/Nov 24 → May/Jun 26

What the papers say

Set in 23 of 33 Paper 2 sittings — about 7 papers in 10.
Worth about 8.9 marks a paper (12% of Paper 2, well under its fair share of 25%).
Last set May/Jun 2026 · 9618/23 · Q4 for 4 marks — in the most recent series.
Set in each of the last 11 series without a miss.
Easing off: about 13.8 marks a paper earlier, 6.7 in the latest years — still examined, just smaller.
Lives on “Complete” and “Identify” — 68% of its questions: you must produce something — code, a diagram, a table — practise doing it, not reading it.
68% of its questions involve a diagram, table or figure — practise with pen and paper.
60% of its questions are set out as code, pseudocode or a table to complete.
Its biggest question so far: 27 marks (May/Jun 2023 · 9618/21 · Q4).
Inside the topic, §9.2 Algorithms carries the most marks (55%) and §9.2 Documenting and converting the least (22%).
It is examined mostly as AO2 (Apply & analyse, 58%), the rest AO3 (42%) — you must apply it to the given data or scenario — work it out, trace it, explain it in context.
The examiner has commented on 30 of its questions — read “What the examiner said” before you practise.

Command words

Share of questions using the word (a question can use several). What each wants →

Question shapes

≤ 6 mk11
7–9 mk14
10–12 mk10
13–15 mk4
16+ mk1

Average 8.9 marks a question · 68% with a figure or table · 60% with code · biggest 27 marks

Assessment objectives — how it is examined

Every part of every current-syllabus question filed under Cambridge's AO1 / AO2 / AO3 (from its command word and what it asks you to do), so you know whether this topic pays for definitions, for applying, or for judging and building.

AO2 58%

AO3 42%

AO1 Knowledge & understanding
AO2 Apply & analyse
AO3 Design, program & evaluate

Paper 2 as a whole

Paper 2	Syllabus	Measured
AO1 Knowledge & understanding	0%	0%
AO2 Apply & analyse	40%	46%
AO3 Design, program & evaluate	60%	54%

Syllabus = Cambridge's grid; measured = the bank's current-syllabus papers.

Inside the topic — every syllabus bullet, measured

Each part of each question is filed under the bullet it examines; the numbers are per Paper 2 sitting, exactly like the topic's. Open a bullet for its own Statometer.

9.1Computational thinking skills#12 of 14 on Paper 2Occasional · 2739% next paper1.5 marks13/33 sittings→ May/Jun 2026Occasional · 2739%
1.5 · 23% of topic13/33May/Jun 2026latest series · →
Rotated in occasionally — the bullet students skip and then meet.Syllabus: abstraction (need, benefits, building an abstract model) and decomposition into sub-problems that become program modules
Next Paper 2
39%
2 in 4
Marks a paper
1.5
2% of the paper · 23% of the topic
Asked in
13 / 33
Paper 2 sittings · 13 questions
Last asked
May/Jun 2026
9618/22 · Q2 · 1 marks · 3-series streak
Asked in 13 of 33 Paper 2 sittings — roughly one paper in 3.
About 1.5 marks a paper (2% of Paper 2; 23% of the topic's marks across its 3 bullets).
Last asked May/Jun 2026 · 9618/22 · Q2 (1 marks) — in the most recent series.
Usually “Complete” or “Identify”: you must produce something — code, a diagram, a table — practise doing it, not reading it.
Biggest chunk of marks so far: 9 in May/Jun 2022 · 9618/22 · Q3.
It is examined mostly as AO2 (Apply & analyse, 60%), the rest AO3 (40%) — you must apply it to the given data or scenario — work it out, trace it, explain it in context.
Last 12 sittings→ Steady
Assessment objectives
AO2 60%
AO3 40%
AO1 Knowledge & understanding
AO2 Apply & analyse
AO3 Design, program & evaluate
Complete62%
Identify54%
Explain39%
Describe31%
Practise its 13 questions Biggest: 9 marks · May/Jun 2022
9.2Algorithms#8 of 14 on Paper 2Core · 5564% next paper3.9 marks21/33 sittings→ May/Jun 2026Core · 5564%
3.9 · 55% of topic21/33May/Jun 2026latest series · →
A regular earner inside the topic — most papers touch it.Syllabus: an algorithm as a sequence of steps; identifier tables; pseudocode with input, process and output using sequence, selection and iteration
Next Paper 2
64%
6 in 10
Marks a paper
3.9
5% of the paper · 55% of the topic
Asked in
21 / 33
Paper 2 sittings · 27 questions
Last asked
May/Jun 2026
9618/23 · Q4 · 4 marks · 11-series streak
Asked in 21 of 33 Paper 2 sittings — about 6 papers in 10.
About 3.9 marks a paper (5% of Paper 2; 55% of the topic's marks across its 3 bullets).
Last asked May/Jun 2026 · 9618/23 · Q4 (4 marks) — in the most recent series.
Asked in each of the last 11 series.
Usually “Identify” or “Complete”: short, precise answers in syllabus words.
Biggest chunk of marks so far: 15.5 in May/Jun 2023 · 9618/21 · Q4.
It is examined mostly as AO3 (Design, program & evaluate, 55%), the rest AO2 (45%) — you must build it — write the pseudocode or program, design the structure.
Last 12 sittings→ Steady
Assessment objectives
AO2 45%
AO3 55%
AO1 Knowledge & understanding
AO2 Apply & analyse
AO3 Design, program & evaluate
Identify44%
Complete37%
Write33%
Explain22%
Practise its 27 questions Biggest: 15.5 marks · May/Jun 2023
9.2Documenting and converting#13 of 14 on Paper 2Occasional · 1926% next paper1.2 marks10/33 sittings↘ Oct/Nov 2025Occasional · 1926%
1.2 · 22% of topic10/33Oct/Nov 20251 series ago · ↘
Rotated in occasionally — the bullet students skip and then meet.Syllabus: structured English, flowcharts and pseudocode (writing one from another); stepwise refinement; logic statements
Next Paper 2
26%
1 in 4
Marks a paper
1.2
2% of the paper · 22% of the topic
Asked in
10 / 33
Paper 2 sittings · 10 questions
Last asked
Oct/Nov 2025
9618/23 · Q2 · 6 marks · 1 series ago
Asked in 10 of 33 Paper 2 sittings — roughly one paper in 3.
About 1.2 marks a paper (2% of Paper 2; 22% of the topic's marks across its 3 bullets).
Last asked Oct/Nov 2025 · 9618/23 · Q2 (6 marks), 1 series ago.
Easing: 2.5 → 0.6 marks a paper.
Usually “Identify” or “Write”: short, precise answers in syllabus words.
Biggest chunk of marks so far: 12 in Oct/Nov 2021 · 9618/21 · Q2.
It is examined almost entirely as AO3 (Design, program & evaluate, 82%) — you must build it — write the pseudocode or program, design the structure.
Last 12 sittings↘ Easing
Assessment objectives
AO2 19%
AO3 82%
AO1 Knowledge & understanding
AO2 Apply & analyse
AO3 Design, program & evaluate
Identify60%
Write50%
Give40%
Draw30%
Practise its 10 questions Biggest: 12 marks · Oct/Nov 2021

32% of the topic's marks sit in question parts that belong to another topic (scenario questions cross sections) or that no bullet claims; they count for the topic, not for a bullet.

Marks a paper, year by year

212223242526

By exam series

May/Jun12/18 · 9.8 mk
Oct/Nov11/15 · 11.9 mk

Practise 40 real questions Smart Notes Quiz Flashcards Every topic on the Statometer

What you need to know3syllabus §9.1, §9.2

9.1Computational thinking skills — abstraction (need, benefits, building an abstract model) and decomposition into sub-problems that become program modules
9.2Algorithms — an algorithm as a sequence of steps; identifier tables; pseudocode with input, process and output using sequence, selection and iteration
9.2Documenting and converting — structured English, flowcharts and pseudocode (writing one from another); stepwise refinement; logic statements

Video lectures15ZAK's YouTube channel · play here

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Open in the video library ZAK's channel

Infographics2draw these the way the examiner expects · download as PNG

Flowchart symbols & the PDLC

O LevelAS

Browse all infographics →

Key terms12use these exact words in the exam

abstraction decompositionidentifier tablestructured Englishflowchartpseudocodesequenceselectioniterationstepwise refinementlogic statementmodule

Dotted terms are defined in the glossary.

Code help4referenced to the Cambridge pseudocode guide

Stack with an array (push/pop)

pseudocode §3, §8.1 Run in Playground

DECLARE Stack : ARRAY[1:5] OF INTEGER
DECLARE Top : INTEGER
Top ← 0
PROCEDURE Push(V : INTEGER)
   IF Top = 5 THEN
      OUTPUT "Stack full"
   ELSE
      Top ← Top + 1
      Stack[Top] ← V
   ENDIF
ENDPROCEDURE
FUNCTION Pop() RETURNS INTEGER
   DECLARE V : INTEGER
   IF Top = 0 THEN
      OUTPUT "Stack empty"
      RETURN -1
   ENDIF
   V ← Stack[Top]
   Top ← Top - 1
   RETURN V
ENDFUNCTION
CALL Push(10)
CALL Push(20)
CALL Push(30)
OUTPUT Pop(), " ", Pop(), " ", Pop(), " ", Pop()

Circular queue with an array

pseudocode Run in Playground

CONSTANT Size = 4
DECLARE Q : ARRAY[0:3] OF STRING
DECLARE Front, Rear, Count : INTEGER
Front ← 0
Rear ← -1
Count ← 0
PROCEDURE Enqueue(V : STRING)
   IF Count = Size THEN
      OUTPUT "Queue full"
   ELSE
      Rear ← (Rear + 1) MOD Size
      Q[Rear] ← V
      Count ← Count + 1
   ENDIF
ENDPROCEDURE
FUNCTION Dequeue() RETURNS STRING
   DECLARE V : STRING
   IF Count = 0 THEN
      RETURN "(empty)"
   ENDIF
   V ← Q[Front]
   Front ← (Front + 1) MOD Size
   Count ← Count - 1
   RETURN V
ENDFUNCTION
CALL Enqueue("A")
CALL Enqueue("B")
OUTPUT Dequeue()
CALL Enqueue("C")
CALL Enqueue("D")
CALL Enqueue("E")
OUTPUT Dequeue(), Dequeue(), Dequeue(), Dequeue()

Binary search (iterative)

pseudocode Run in Playground

DECLARE A : ARRAY[1:8] OF INTEGER
DECLARE Low, High, Mid, Target, i : INTEGER
DECLARE Found : BOOLEAN
FOR i ← 1 TO 8
   A[i] ← i * 3     // 3 6 9 12 15 18 21 24 (sorted)
NEXT i
Target ← 18
Low ← 1
High ← 8
Found ← FALSE
WHILE Low <= High AND NOT Found
   Mid ← (Low + High) DIV 2
   IF A[Mid] = Target THEN
      Found ← TRUE
   ELSE
      IF A[Mid] < Target THEN
         Low ← Mid + 1
      ELSE
         High ← Mid - 1
      ENDIF
   ENDIF
ENDWHILE
OUTPUT "Found: ", Found, " at ", Mid

Insertion sort

pseudocode Run in Playground

DECLARE A : ARRAY[1:6] OF INTEGER
DECLARE i, j, Key : INTEGER
A[1] ← 9
A[2] ← 4
A[3] ← 7
A[4] ← 1
A[5] ← 8
A[6] ← 2
FOR i ← 2 TO 6
   Key ← A[i]
   j ← i - 1
   WHILE j >= 1 AND A[j] > Key
      A[j + 1] ← A[j]
      j ← j - 1
   ENDWHILE
   A[j + 1] ← Key
NEXT i
FOR i ← 1 TO 6
   OUTPUT A[i]
NEXT i

💡 The WHILE condition relies on short-circuit AND (j >= 1 checked first) — the Playground does this like most languages.

Playground examples19runnable programs for this topic

Swap two variables
The three-line swap with a temporary variable — a favourite trace-table question.
O LevelASPseudocodeBasics & data types §1.5
Run
Maximum, minimum & average
The standard algorithm: start Highest very low and Lowest very high, then update as you go.
O LevelASPseudocodeIteration 2210 §7.1 standard methods
Run
Counting — how many passed?
Two counters updated inside a loop, then a percentage.
O LevelASPseudocodeIteration 2210 §7.1 standard methods
Run
Total, average and position of the maximum
Keep the index of the best value, not just the value, so you can say where it was.
O LevelASPseudocodeArrays §3.2
Run
Stepwise refinement — a bank menu built from modules
The main program only shows the menu and CALLs procedures; each module does one job (a structure chart in code).
ASPseudocodeProcedures & functions §8.1 · 9618 §9.1
Run
Linear search
Check each element in turn and stop as soon as the target is found.
O LevelASPseudocodeSearching 2210 §7.1 / 9618 §9.2
Run
Linear search — every match
Do not stop at the first hit: report every position and count them.
O LevelASPseudocodeSearching 2210 §7.1
Run
Binary search (iterative)
Only works on sorted data: halve the search range each time by comparing with the middle element.
ASA2PseudocodeSearching 9618 §19.1
Run
Bubble sort
Compare neighbours and swap; after each pass the largest value has bubbled to the end.
O LevelASPseudocodeSorting 2210 §7.1 / 9618 §9.2
Run
Bubble sort with a Swapped flag
Stop early when a whole pass makes no swaps — the efficient version examiners like.
ASA2PseudocodeSorting 9618 §9.2, §19.1
Run
Insertion sort
Take each value in turn and slide it left into the sorted part of the array.
ASA2PseudocodeSorting 9618 §19.1
Run
Sort names alphabetically
Bubble sort works on strings too: "Ali" < "Zara" compares character codes.
O LevelASPseudocodeSorting 2210 §7.1
Run
Sort parallel arrays — a leaderboard
Sort marks descending and swap the names at the same time so they stay matched.
ASPseudocodeSorting 9618 §9.2, §10.2
Run
AS Paper 2 — library loans
An array of records, a search function, procedures for borrowing and reporting, all driven by a menu.
ASPseudocodeExam-style tasks §4.2, §8
Run
Totalling, counting, max, min, average
The standard loop pattern with a list — and then the built-ins sum(), max(), min(), len() that do it in one line.
O LevelASPythonIteration §7.1 ↔ Python
Run
Linear search
Walk the list until you find the target — the exam wants the loop, not list.index().
O LevelASPythonSearching §7 ↔ Python
Run
Binary search — iterative and recursive
Halve the search space each time; the list must be sorted. Both versions, with the number of comparisons.
ASA2PythonSearching §7 ↔ Python
Run
Bubble sort with a swapped flag
The classic Paper 2 / Paper 4 sort. Open the Trace tab to watch the swaps.
O LevelASPythonSorting §7 ↔ Python
Run
Insertion sort
Take each item and slide it left into the sorted part. Compare with sorted() and .sort() at the end.
ASA2PythonSorting §7 ↔ Python
Run

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Quiz: Algorithm Design & Problem-Solving (40)🃏 Flashcards: mix this topic (31)📐 Computational thinking & design tools (15)🧭 Algorithms — pseudocode, flowcharts & refinement (16)Past-paper questions (40)🔀 Flowchart Studio 📊 Sorting & searching visualiser 📋 Trace tables 🪪 Identifier table (Playground)

Everything for this topic — study hub

Statometer — what 33 real papers say about this topic and each of its 3 syllabus bullets

What you need to know3syllabus §9.1, §9.2

Video lectures15ZAK's YouTube channel · play here

Queue ADT · Pseudocode · AS/A Level

Stack ADT · Introduction · Pseudocode · AS/A Level

Pseudocode Commands Syntaxes · W21 P22 Q7-8 · AS Level

Bubble Sort · Array Handling · Pseudocode · VB.net · PP Question · AS/A Level

Structured Programming · Lecture 2/2 · AS

Structured Programming · Lecture 1/2 · AS

Infographics2draw these the way the examiner expects · download as PNG

Key terms12use these exact words in the exam

Code help4referenced to the Cambridge pseudocode guide

Playground examples19runnable programs for this topic

Ready to check you know it?