GATE CSE 2025 Session 2 Q24: Languages accepted by a deterministic PDA

Which ONE of the following languages is accepted by a deterministic push down automaton?

Try it: multiple choice: exactly one correct option

Wrong answer costs 1/3 mark in GATE.

Show answer and explanation

Answer: A (official GATE 2025 final answer key)

Concept used: Regular ⊂ DCFL ⊂ CFL: a DPDA can simulate a DFA but not every NPDA.

First step: A DFA is a DPDA that ignores its stack; recall a CFL that is not deterministic, such as even-length palindromes.

Full step-by-step solution

Detailed working, common mistakes and linked mock tests will be available with a free GATEiit account. Log-in is coming soon.

Share this question

Source: official GATE 2025 Session 2 CS question paper and final answer key, organised by IIT Roorkee. Question paper · Answer key