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Module 5 · Dijkstra's Algorithm

Lesson 1 · The Grid as a Graph — Knowledge Checks

Name Date

  1. Why can't the Manhattan algorithm route around a blocked intersection?

    1. A.It runs too slowly
    2. B.It only knows one fixed strategy (rows then columns) and has no concept of obstacles
    3. C.It can, if you turn it off and on again
    4. D.The robot has no wheels

    Answer Why?

  2. On a 3×3 grid, how many neighbors does the interior node (1,1) have?

    1. A.2
    2. B.3
    3. C.4
    4. D.8

    Answer Why?

  3. After (1,1) is blocked, how many neighbors does (0,1) have?

    1. A.3 — nothing changed
    2. B.2 — it lost its downward connection to (1,1)
    3. C.4
    4. D.0

    Answer Why?

  4. With (1,0) blocked, the shortest path from (0,0) to (2,0) is 4 steps, but the Manhattan distance is 2. What does that tell you?

    1. A.The Manhattan distance is wrong
    2. B.With obstacles, the real shortest path can be longer than the Manhattan distance
    3. C.Obstacles always add exactly 2 steps
    4. D.The destination is unreachable

    Answer Why?

  5. In computer science, what does the word 'graph' mean?

    1. A.A bar chart or scatter plot
    2. B.A network of nodes connected by edges
    3. C.A grid of pixels
    4. D.A line showing data over time

    Answer Why?