A* and D* Algorithms MCQs

1. What is the primary purpose of the A algorithm?*

A) Sorting elements
B) Pathfinding and graph traversal
C) Data compression
D) Image processing

Answer: B) Pathfinding and graph traversal

2. Which heuristic function is commonly used in the A algorithm?*

A) Manhattan distance
B) Euclidean distance
C) Chebyshev distance
D) All of the above

Answer: D) All of the above

3. In A, what does the f(n) value represent?*

A) The cost to reach node n
B) The estimated cost from node n to the goal
C) The sum of the actual cost to reach n and the estimated cost to the goal
D) The heuristic cost

Answer: C) The sum of the actual cost to reach n and the estimated cost to the goal

4. Which of the following is true about the A algorithm?*

A) It is always optimal and complete
B) It is always optimal but not complete
C) It is complete but not always optimal
D) It is neither complete nor optimal

Answer: C) It is complete but not always optimal

5. In the A algorithm, what is the purpose of the heuristic function h(n)?*

A) To calculate the path cost
B) To estimate the cost from node n to the goal
C) To store the parent node
D) To keep track of visited nodes

Answer: B) To estimate the cost from node n to the goal

6. What type of search strategy does A employ?*

A) Depth-first search
B) Breadth-first search
C) Best-first search
D) Random search

Answer: C) Best-first search

7. Which property does the heuristic function h(n) need to guarantee that A is optimal?*

A) It needs to be consistent (monotonic)
B) It needs to be random
C) It needs to be zero
D) It needs to be exponential

Answer: A) It needs to be consistent (monotonic)

8. What is the main advantage of using the D algorithm over A?**

A) It provides a more detailed path
B) It is more efficient in static environments
C) It is designed for dynamic environments
D) It has better heuristic functions

Answer: C) It is designed for dynamic environments

9. In the D algorithm, what happens when an obstacle is detected in a previously explored area?*

A) The algorithm recalculates the entire path from scratch
B) The algorithm updates only the affected part of the path
C) The algorithm ignores the obstacle
D) The algorithm stops and fails

Answer: B) The algorithm updates only the affected part of the path

10. What is the primary goal of the D Lite algorithm?*

A) To improve pathfinding in static environments
B) To provide a simpler and more efficient version of D*
C) To enhance the performance of A*
D) To handle dynamic obstacle avoidance

Answer: B) To provide a simpler and more efficient version of D*

11. Which function in the A algorithm is used to track the cost of the path from the start node to the current node?*

A) g(n)
B) h(n)
C) f(n)
D) c(n)

Answer: A) g(n)

12. In the A algorithm, what is the role of the open list?*

A) To store nodes that have been fully explored
B) To store nodes that need to be explored
C) To store nodes that are currently not reachable
D) To store nodes that are blocked by obstacles

Answer: B) To store nodes that need to be explored

13. Which of the following statements is true about the D algorithm?*

A) It is used for offline pathfinding
B) It requires a static map of the environment
C) It updates paths dynamically as new information becomes available
D) It does not handle obstacles

Answer: C) It updates paths dynamically as new information becomes available

14. What does the open list in the A algorithm contain?*

A) Nodes that have been visited
B) Nodes that are yet to be expanded
C) Nodes that are part of the final path
D) Nodes that are unreachable

Answer: B) Nodes that are yet to be expanded

15. What is the key difference between the A algorithm and Dijkstra’s algorithm?*

A) A* uses a heuristic to guide the search, while Dijkstra’s algorithm does not
B) Dijkstra’s algorithm uses a heuristic to guide the search, while A* does not
C) A* is less efficient than Dijkstra’s algorithm
D) Dijkstra’s algorithm is designed for dynamic environments, while A* is not

Answer: A) A* uses a heuristic to guide the search, while Dijkstra’s algorithm does not

16. In the context of the A algorithm, what is a node?*

A) A point in the search space representing a location or state
B) A function used to calculate costs
C) A path from the start to the goal
D) An obstacle in the environment

Answer: A) A point in the search space representing a location or state

17. What is the purpose of the closed list in the A algorithm?*

A) To store nodes that are yet to be expanded
B) To store nodes that have been fully explored
C) To store nodes that are blocked by obstacles
D) To store nodes that are part of the final path

Answer: B) To store nodes that have been fully explored

18. Which algorithm is particularly useful in applications where the environment changes frequently?

A) A*
B) Dijkstra’s Algorithm
C) D*
D) Greedy Best-First Search

Answer: C) D*

19. In A, what does the h(n) function represent?*

A) The cost of moving to node n
B) The total cost from the start node to node n
C) The estimated cost from node n to the goal node
D) The distance between two nodes

Answer: C) The estimated cost from node n to the goal node

20. What does the D algorithm primarily optimize for?*

A) Static pathfinding
B) Memory usage
C) Pathfinding in dynamic environments
D) Sorting of nodes

Answer: C) Pathfinding in dynamic environments

21. What does the term consistent heuristic mean in the context of the A algorithm?*

A) The heuristic function provides the same estimate for all nodes
B) The heuristic function never overestimates the true cost
C) The heuristic function is the same for every iteration
D) The heuristic function is always zero

Answer: B) The heuristic function never overestimates the true cost

22. Which of the following is NOT a feature of the D algorithm?*

A) It updates paths when obstacles are detected
B) It requires a complete map of the environment
C) It adjusts to changes in the environment dynamically
D) It performs efficient re-planning in response to changes

Answer: B) It requires a complete map of the environment

23. How does the A algorithm determine the priority of nodes in the open list?*

A) Based on the g(n) value
B) Based on the h(n) value
C) Based on the f(n) value
D) Based on the distance between nodes

Answer: C) Based on the f(n) value

24. In the D algorithm, what is the role of the delta parameter?*

A) To define the amount by which paths are adjusted when new information is received
B) To specify the initial cost of a path
C) To set the goal node for the pathfinding
D) To control the number of nodes in the open list

Answer: A) To define the amount by which paths are adjusted when new information is received

25. What is the main advantage of using the D Lite algorithm over the original D?*

A) It is faster and requires less memory
B) It supports offline pathfinding
C) It can handle larger maps
D) It is more complex and less efficient

Answer: A) It is faster and requires less memory

26. Which of the following is a common application of the A algorithm?*

A) Game development for pathfinding
B) Data compression
C) Image recognition
D) Network routing

Answer: A) Game development for pathfinding

27. In the A algorithm, what is the function of the g(n) value?*

A) The estimated cost from node n to the goal
B) The cost to reach node n from the start node
C) The heuristic estimate of the path cost
D) The total path cost from the start to the goal

Answer: B) The cost to reach node n from the start node

28. What does the path smoothing technique in A aim to achieve?*

A) To make the path more direct and less jagged
B) To increase the length of the path
C) To adjust the path dynamically
D) To improve the heuristic function

Answer: A) To make the path more direct and less jagged

29. Which heuristic function is suitable for a grid-based pathfinding problem?

A) Manhattan distance
B) Euclidean distance
C) Diagonal distance
D) All of the above

Answer: D) All of the above

30. Which aspect of the D algorithm allows it to adapt to changes in the environment?*

A) The use of a static heuristic function
B) The ability to update the path incrementally
C) The use of a complete map of the environment
D) The reliance on precomputed paths

Answer: B) The ability to update the path incrementally