Q32.Marks: +2.0UGC NET Paper 2: Computer Science 2020
Match List I with List II
List I
List II
(A) Greedy Best-First Search
(I) Space complexity is O(d) where d = depth of the deepest optimal solution
(B) A*
(II) Incomplete even if the search space is finite.
(C) Recursive Best-First Search
(III) Optimal if optimal solution is reachable: otherwise, returns the best reachable optimal solution.
(D) SMA*
(IV) Computation and space complexity is too high.
Choose the correct answer from the options given below:
1.A - II, B - IV, C - I, D - III ✓ Correct
2.A - II, B - III, C - I, D - IV
3.A - III, B - II, C - IV, D - I
4.A - III, B - IV, C - II, D - I
Solution
The correct answer is option 1.
Key Points
Greedy best-first search algorithm always selects the path which appears best at that moment. It is the combination of depth-first search and breadth-first search algorithms.
Time complexity: The worst-case time complexity of the greedy best-first search is O(bm).
Space Complexity: The worst-case space complexity of the greedy best-first search is O(bm). Where m is the maximum depth of the serach space
Complete: Greedy best-first search is also incomplete, even if the state space is finite.
Optimal: Greedy best-first search algorithm is not optimal.
A* is optimal and complete but time complexity and space complexity too high. It requires more computation.
Recursive Best-First Search retents more memory knowledge but uses only O(bd) memory
Memory Simplified Bound A* such as A* Optimal if you can get optimal solution otherwise as it is memory-bound.
∴ Hence the correct answer isA - II, B - IV, C - I, D - III.