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Algorithms and Problem Solving

Quick questions on Graph traversal with BFS and DFS explained: H2 Computing

5short Q&A pairs drawn directly from our worked dot-point answer. For full context and worked exam questions, read the parent dot-point page.

What is breadth-first search (BFS)?
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BFS uses a queue (first in, first out). It visits a node, enqueues its unvisited neighbours, then dequeues the next node - so it fans out level by level from the start:
What is depth-first search (DFS)?
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DFS uses a stack (last in, first out), or recursion via the call stack. It goes as deep as possible along one path, then backtracks:
What is q1?
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Which data structure drives breadth-first search, and which drives depth-first search? [2 marks]
What is q2?
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Why does BFS find the shortest path (in edges) in an unweighted graph? [2 marks]
What is q3?
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Give one task for which depth-first search is better suited than breadth-first search. [1 mark]

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