IB Computer Science HL · Year 2 · Lesson 21

ADTs + linked-list evaluation

Abstract data types separate what operations mean from how they are implemented, helping you choose structures by behaviour and trade-offs.

Paper 250 minutesB4.1.1 · B4.1.2
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Today’s targets

What you need to be able to do

2 / 7
  • ExplainThe properties and purpose of ADTs in programming
  • EvaluateLinked lists
B4.1.1B4.1.2
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 is an abstract data type (ADT)?: A high-level specification of a kind of data and the operations allowed on it, independent of a particular implementation.
  • Which linked-list forms are required?: Singly linked, doubly linked, and circular linked lists.
  • What does a linked-list node normally contain?: Stored data plus one or more links/references to other nodes.
  • Which basic linked-list operations should you know?: Insertion, deletion, traversal, and search.
  • What is a key trade-off between linked lists and arrays?: Linked lists support flexible insertion/deletion without shifting contiguous elements, but they use link memory and do not provide direct indexed access like arrays.
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B4.1.1 + B4.1.2 · Learn

Core knowledge and application

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B4.1.1Explain

The properties and purpose of ADTs in programming

Abstract data types separate what operations mean from how they are implemented, helping you choose structures by behaviour and trade-offs.

Exam moveGive the mechanism or relationship and make the reasons/causes explicit.
Required detail 1The core principles of ADTs, including their purpose in providing a high-level description of data structures and their associated operations
Assessment boundaryPaper 2

Explain it without notes

Explain: The properties and purpose of ADTs in programming in the context of a system that needs efficient insertion, search and set membership.

  • The core principles of ADTs, including their purpose in providing a high-level description of data structures and their associated operations
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
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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.
  • The core principles of ADTs, including their purpose in providing a high-level description of data structures and their associated operations
  • Lists must include singly, doubly, circular
  • Sketch of linked lists and implementation of basic operations diagrammatically, 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.
  1. Explain: The properties and purpose of ADTs in programming in the context of a system that needs efficient insertion, search and set membership.
  2. Evaluate: Linked lists 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 21.