IB Computer Science HL · Year 2 · Lesson 24
Linked-list operations and applications
Abstract data types separate what operations mean from how they are implemented, helping you choose structures by behaviour and trade-offs.
Paper 250 minutesB4.1.2 · B4.1.3
Use Next or the arrow keys.
Today’s targets
What you need to be able to do
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- EvaluateLinked lists
- Construct + applyAnd apply linked lists: singly, doubly and circular
- RetrieveReconnect today’s new material to previously taught content from this topic.
B4.1.2B4.1.3
Paper 2 lensMatch the depth of every response to the command term. Previously learned content can move quickly, but retrieval must still be accurate.
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Retrieve
Rapid Recall Deck
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Say the answer aloud before flipping. Mark secure knowledge quickly and spend time on the gaps.
- What happens during linked-list insertion?: A new node is created and surrounding references are updated so it becomes part of the chain.
- What happens during linked-list deletion?: References are redirected around the removed node so the remaining list stays connected.
- What is traversal in a linked list?: Visiting nodes in sequence by following links from one node to the next.
- Why can insertion and deletion be efficient in a linked list?: Once the relevant position/node is known, references can be changed without shifting a block of contiguous elements.
- Why can indexed access be slower in a linked list than in an array?: A linked list must follow references from a starting node; an array can calculate the address of an indexed element directly.
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B4.1.2 + B4.1.3 · Learn
Core knowledge and application
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B4.1.2Evaluate
Linked lists
Abstract data types separate what operations mean from how they are implemented, helping you choose structures by behaviour and trade-offs.
Exam moveWeigh strengths and limitations in context, then reach a supported judgement.
Required detail 1Lists must include singly, doubly, circular
Required detail 2Sketch of linked lists and implementation of basic operations diagrammatically, such as insertion, deletion, traversal, search
Required detail 3The advantages and disadvantages of using linked lists over other data structures like arrays, particularly in terms of memory utilization and performance
Assessment boundaryPaper 2
Explain it without notes
Evaluate: Linked lists in the context of a system that needs efficient insertion, search and set membership.
- Lists must include singly, doubly, circular
- Sketch of linked lists and implementation of basic operations diagrammatically, such as insertion, deletion, traversal, search
- The advantages and disadvantages of using linked lists over other data structures like arrays, particularly in terms of memory utilization and performance
B4.1.3Construct + apply
And apply linked lists: singly, doubly and circular
Abstract data types separate what operations mean from how they are implemented, helping you choose structures by behaviour and trade-offs.
Exam moveBuild the structure/solution and use it correctly in a new context.
Required detail 1The basic operations on a linked list, such as insertion, deletion, traversal, search
Assessment boundaryPaper 2
Explain it without notes
Construct + apply: And apply linked lists: singly, doubly and circular in the context of a system that needs efficient insertion, search and set membership.
- The basic operations on a linked list, such as insertion, deletion, traversal, search
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Worked example · B4.1.2 / B4.1.3
Linked-list operations: insertion, deletion, traversal and search
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SearchStart at head; compare current.data with target; advance to current.next until found or null/head is reached.
TraverseVisit each node exactly once while following links in order.
Insert after currentSet new.next to current.next, then current.next to new.
Delete after currentRedirect current.next to the node after the node being removed.
Diagram firstWhen asked to describe an insertion, draw the before/after links. The critical idea is preserving access to the remainder of the list while pointers are updated.
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Apply
Transfer to a new scenario
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ScenarioA system that needs efficient insertion, search and set membership needs a design or technical decision related to today’s topic. Explain what matters and why.
- Lists must include singly, doubly, circular
- Sketch of linked lists and implementation of basic operations diagrammatically, such as insertion, deletion, traversal, search
- The basic operations on a linked list, such as insertion, deletion, traversal, search
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Exam lens
Paper 2 practice
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Build the response before checking notesUse precise terminology and match the required depth.
- Evaluate: Linked lists in the context of a system that needs efficient insertion, search and set membership.
- Construct + apply: And apply linked lists: singly, doubly and circular in the context of a system that needs efficient insertion, search and set membership.
Self-checkAnswer the exact command term. For explain, include mechanism/reason; for compare, pair criteria; for discuss/evaluate/justify, build supported reasoning and a conclusion.
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Homework
Finish the learning cycle
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IA — main task
Continue Criterion D development. Keep code readable, record meaningful implementation decisions, and maintain testing/evidence notes as you work.
Syllabus — short
Complete one targeted Paper 2/Paper 1 retrieval task from today’s lesson.
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End of Lesson 24.