Standard Searching, Sorting and Traversal Algorithms
Explaining, tracing and selecting standard algorithms for searching, sorting and traversing common structures.
How to study A-level Computer Science
Define the problem and representation, trace the state change, justify the algorithm or architecture, then test the result against requirements, evidence and constraints.
Core concepts
Concept 1
Linear and binary search have different data preconditions and performance characteristics.
Exam cue: Check whether the data is ordered before selecting binary search.
Concept 2
Sorting methods differ in strategy, time and space behaviour, stability and suitability for particular data.
Exam cue: Describe the invariant or progress made after each pass, comparison or recursive call.
Concept 3
Tree or graph traversal maintains an explicit frontier and a rule for the order in which nodes are processed.
Exam cue: Relate breadth-first and depth-first traversal to queue and stack behaviour.
Risk pitfalls and guardrails
Claiming binary search works on an unsorted collection.
Guardrail: Do not substitute a memorised definition or generic advantage until you have identified the input, state, stakeholder and constraint in the task.
Naming a sorting algorithm without explaining its steps.
Guardrail: Do not substitute a memorised definition or generic advantage until you have identified the input, state, stakeholder and constraint in the task.
Revisiting graph nodes indefinitely because no visited state is recorded.
Guardrail: Do not substitute a memorised definition or generic advantage until you have identified the input, state, stakeholder and constraint in the task.
Memory anchors
Linear Search
Inspect items in sequence until the target is found or the data is exhausted.
Binary Search
Repeatedly halve an ordered search interval.
Merge Sort
Divide, sort the parts and merge them in order.
Breadth-first
Breadth-first traversal normally uses a queue to explore by distance or level.
Depth-first
Depth-first traversal normally uses a stack or recursion to follow one branch before backtracking.
Checkpoint rule
Do the check-up only after you can summarize each concept in one sentence and identify one dangerous pitfall from memory.
Knowledge Check (after reading)
Short check-up to confirm understanding of this module.
Check-up Questions
What precondition is required for binary search?
A linear search checks a list of n items for an absent target. How many equality checks are needed in the worst case?
Answer all questions to submit.
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Move forward only after this module is stable.
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