Question

Which of the following permutations can be obtained in the output (in the same order) using a stack assuming that the input is the sequence 1, 2, 3, 4, 5 in that order?
(A) 2
(B) 3
(C) 1
(D) 4
(E) 5
Choose the correct answer from the options given below:

• A. (B), (D), (E), (A), (C)
• B. (B), (D), (A), (E), (C)
• C. (A), (D), (B), (C), (E)
• D. (E), (D), (C), (A), (B)

Hint:

Ensure you follow the LIFO property of stacks and Not all permutations are achievable with stack operations.

Answer 1

The Correct Option is A

A stack's operational order limits the permutations that can be generated. Systematically tracing these operations reveals the valid sequence: (B), (D), (E), (A), (C).