# Theory of Computation – GATE CSE Previous Year Questions

Solving **GATE Previous Year’s Questions** (PYQs) not only clears the concepts but also helps to gain flexibility, speed, accuracy, and understanding of the level of questions generally asked in the GATE exam, and that eventually helps you to gain good marks in the examination. Previous Year Questions help a candidate practice and revise for GATE, which helps **crack GATE** with a good score.

**Theory of Computation Previous Year GATE Questions** help in analyzing the question pattern of a subject and marking scheme as well as it helps in time management which overall increases the score in the GATE exam. With regular practice of PYQs, candidates can easily crack GATE with a good GATE Score.

Before 2006, questions asked in GATE were mainly theoretical, but in recent years, the questions asked were multiple-choice questions with a single correct option or multiple correct options. We are looking to provide the multiple-choice questions that are asked in GATE.

## Theory of Computation GATE Previous Year Questions

In this article, we are mainly focusing on the Theory of Computation GATE Questions that are asked in Previous Years with their solutions, and where an explanation is required, we have also provided the reason.

In the **Theory of Computation**, we will deal with the following concepts. We have also provided GATE Previous Year’s Questions on these topics. Here is the list of those topics along with their links.

- Finite Automata and Regular Language
- Push Down Automata and Context-Free language
- Recursively Enumerable Language and Turing Machine
- Undecidability

Below mentioned are the links to the **Theory of Computation PYQ’s** pages. On each page, you will get the questions asked in TOC along with the years asked.

GATE TOC Previous Year Questions |
---|

Automata Theory | Set 1, 2 |

Automata Theory | Set 3 |

Automata Theory | Set 4 |

Automata Theory | Set 5 |

Automata Theory | Set 6 |

Also, here we are going to discuss some basic PYQs related to the Theory of Computation.

1.Consider the following statements. [GATE CSE 2020]

I.If L_{1}∪ L_{2}is regular, then both L_{1}and L_{2}must be regular.II.The class of regular languages is closed under infinite union.Which of the above statements is/are

TRUE?(A)

Ionly(B)

IIonly(C) Both

IandII(D) Neither

InorII

Solution:Correct answer is (D)

For more, refer to GATE | GATE CS 2020 | Question 18.

2. Consider the language L = { a^{n}∣ n≥0 }∪{ a^{n}b^{n}∣ n≥0 } and the following statements.

I. L is deterministic and context-free.

II. L is context-free but not deterministic context-free.

III. L is not LL(k) for any k.

Which of the above statements is/are TRUE? [GATE CSE 2020](A) I only

(B) II only

(C) I and III only

(D) III only

Solution:Correct answer is (C)

For more, refer to GATE | GATE CS 2020 | Question 20.

3.Which one of the following languages over the alphabet {0,1} is described by the regular expression: (0+1)*0(0+1)*0(0+1)*? [GATE CSE 2019](A) The set of all strings containing the substring 00.

(B) The set of all strings containing at most two 0’s.

(C) The set of all strings containing at least two 0’s.

(D) The set of all strings that begin and end with either 0 or 1.

Solution:Correct answer is (C)

For more, refer to GATE | GATE-CS-2009 | Question 14.

4.Language L1 is defined by the grammar: S1 −> aS1b|∈Language L2is defined by the grammar: S2−> abS2|∈ [GATE CSE 2016]

Consider the following statements:P: L1 is regularQ: L2 is regularWhich one of the following is

TRUE?(A) Both P and Q are true

(B) P is true and Q is false

(C) P is false and Q is true

(D) Both P and Q are false

Solution:Correct answer is (C)

For more, refer to GATE | GATE-CS-2016 (Set 2) | Question 27.

5. Consider the languages L1 = ∅ and L2 = {a}. Which one of the following represents L1L2* U L1*? [GATE CSE 2013](A) {

∈}(B) ∅

(C) a*

(D) {

∈,a}

Solution:Correct answer is (A)

For more, refer to GATE | GATE CS 2013 | Question 8.

## GATE CSE Previous Year Question Papers

These previous year’s questions help you in understanding the question patterns followed by GATE that directly help a candidate in scoring good marks in GATE. Below are the mentioned links of year-wise GATE Previous Question Papers.

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