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Previous Year Question Paper

CS-501 - Theory of Computation

May 2023•CSE•SEMESTER-5
May 2023
Max Marks: 70
Duration: 3 Hours
Instructions:

• Attempt any five questions.

• All questions carry equal marks.

Q.1
Unit 1

Convert the following Moore machine to Mealy.

i) alt=''

ii) alt=''

Q.2
a)Unit 2

For Σ={a,b}\Sigma = \{a, b\}, construct DFA's that accept the sets consisting of

i) All the strings with exactly one 'a'.

ii) All the string with atleast one 'a'.

iii) All strings with atleast one 'a' and followed by exactly two b's.

Q.3
Unit 2

Describe the following sets by regular expression.

i) Strings containing 1100 as substrings.

ii) The set of all strings of 0's are 1's ending with 00.

iii) ${\Lambda, a, aa, aaa, \dots}

Q.4
a)Unit 2

Explain Arden's theorem and Pumping Lemma.

b)Unit 3

What is Ambiguity? Explain taking any two examples.

Q.5
a)Unit 3

Design a CFG.

i) L(G)={aibck∣i≠j (or) j≠k}L(G)=\{a^ib^ck \mid i \ne j \text{ (or) } j \ne k\}

ii) L(G)={aib2i∣i≥0}L(G)=\{a^ib^{2i} \mid i \ge 0\}

b)Unit 3

Define a context free grammar with example.

Q.6
a)Unit 4

Explain DPDA and NPDA with taking a suitable example.

b)Unit 5

Explain Recursively enumerable language and decidability.

Q.7
Unit 4

Design a Push down automata.

i) anb3n,n≥1a^nb^{3n}, n \ge 1

ii) wwR,w∈{a,b}2ww^R, w \in \{a, b\}^2

Q.8
i)Unit 5

Halting problem

ii)Unit 5

Turing machine

iii)Unit 3

Chomsky Normal form

iv)Unit 2

2 way DFA