GateQA — Free GATE CS Preparation Platform

GateQA is a free GATE CS preparation platform featuring 3,500+ previous-year questions (1987–2026), 36,000+ aptitude questions, subject-wise and year-wise mock tests, performance analytics, and full offline support. Practice Operating Systems, Algorithms, DBMS, Computer Networks, Theory of Computation, Discrete Mathematics, Compiler Design, Digital Logic, and more.

Who will conduct GATE 2027?

Loading GateQA

GATE CS Subject

Theory of Computation GATE CS Questions

Overview & Analysis

Theory of Computation (TOC) is a beautiful, highly structured subject yielding 6 to 8 marks. It defines the mathematical models of computation and formal grammar classification.

The syllabus focuses on regular languages (DFAs, NFAs, regular expressions), context-free languages (CFGs, PDAs), Turing machines, and the Chomsky hierarchy, alongside decidability and undecidability proofs.

Frequently Asked Questions (FAQ)

Q: How do I prove a language is context-free but not regular for GATE?

A: You can use the Pumping Lemma for regular languages to show contradiction, or identify if the language requires a single stack memory comparison (e.g., matching brackets or counts) which context-free languages support.

Q: What are the common undecidable problems in TOC?

A: The Halting Problem for Turing machines, the Post Correspondence Problem (PCP), and checking if a Turing machine accepts a regular language are all classic examples of undecidable problems.

This static SEO snapshot loads the full interactive GateQA app when JavaScript is available.