Lesson 4.3.6.1

4.3.6.1 Dijkstra's shortest path algorithm Quiz: AQA Computer Science, Unit 3

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson 4.3.6.1, Dijkstra's shortest path algorithm: 20 multiple choice questions for the AQA Computer Science (7517), Unit 3: Fundamentals of algorithms, written with Revision Ninja.

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The 20 questions

  1. What does Dijkstra's algorithm find on a weighted graph?

    • Maximum flow
    • Shortest path
    • Topological sort
    • Minimum spanning tree

  2. Dijkstra's shortest path algorithm belongs to which category in the specification?

    • Sorting
    • Optimisation
    • Encryption
    • Parsing

  3. Dijkstra's algorithm requires edge weights to be which kind of values?

    • Non-negative
    • Integers only
    • Negative only
    • All equal to 1

  4. Which real-world application uses Dijkstra's algorithm?

    • File compression
    • Syntax parsing
    • Database indexing
    • Sat-nav route planning

  5. Which node does Dijkstra's algorithm select next at each step?

    • Nearest unvisited node
    • Most connected node
    • Furthest unvisited node
    • Random unvisited node

  6. What skill is required for Dijkstra's algorithm in AQA exams?

    • Tracing the algorithm
    • Writing pseudo-code
    • Proving correctness
    • Recalling the code

  7. Graph: S-A weight 4, S-B weight 1, B-A weight 2, A-T weight 3, B-T weight 6. What is the shortest distance from S to T?

    • 6
    • 4
    • 7
    • 10

  8. In the same graph (S-A 4, S-B 1, B-A 2, A-T 3, B-T 6), what is the shortest distance from S to A?

    • 3
    • 2
    • 6
    • 4

  9. In the same graph, which node is finalised first after the source S?

    • B, with tentative distance 1
    • All nodes simultaneously
    • A, with tentative distance 4
    • T, with tentative distance 6

  10. On a graph where every edge has weight 1, Dijkstra's algorithm gives the same result as which search?

    • Binary search
    • Breadth-first search
    • Bubble sort
    • Depth-first search

  11. Graph: S-A weight 2, A-T weight 2, S-T weight 5. What is the shortest distance from S to T?

    • 5
    • 2
    • 4
    • 7

  12. Which edge property can cause Dijkstra's algorithm to fail?

    • Negative weights
    • Directed edges
    • Large weights
    • Zero weights

  13. Dijkstra's algorithm is an example of which kind of algorithm?

    • Greedy
    • Randomised
    • Brute force
    • Backtracking

  14. Graph: A-B weight 1, B-C weight 1, C-D weight 1, A-D weight 5. What is the shortest distance from A to D?

    • 7
    • 3
    • 5
    • 1

  15. During Dijkstra's algorithm the source has distance 0, and a neighbour X is joined to it by an edge of weight 7. What tentative distance does X receive?

    • Infinity
    • 0
    • 7
    • 14

  16. With a binary heap, what is the usual time complexity of Dijkstra's algorithm on V vertices and E edges?

    • O(V^2) only
    • O(n) always
    • O(2^V)
    • O((V + E) log V)

  17. In a satnav graph, what do edge weights represent?

    • Road names
    • Traffic lights
    • Travel cost
    • Node count

  18. Graph: S-A 1, S-B 4, A-B 2, B-T 1, A-T 6. What is the shortest distance from S to T?

    • 5
    • 6
    • 7
    • 4

  19. Dijkstra's algorithm finds the shortest path from a single source under which condition?

    • Acyclic graphs only
    • Negative edge weights
    • Unweighted edges only
    • Non-negative edge weights

  20. What does breadth-first search minimise when finding a path in a graph?

    • Maximum edge weight
    • Number of edges
    • Node traversal speed
    • Total edge weight

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