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GATE CS Theory of Computation questions

Practise Theory of Computation questions for GATE CS. Explore official PYQs and original subject-wise quizzes, check answers and view available solutions. Free, no sign-in.

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Official PYQ2001Theory of ComputationRegular and Context-free LanguagesMCQ · 1 mark
Consider the following languages: L1={ww∣w∈{a,b}∗}L1=\left\{ww \mid w \in \{a,b\}^*\right\} L2={wwR∣w∈{a,b}∗,wR is the reverse of w}L2=\left\{ww^R \mid w \in \{a,b\}^*, w^R \text{ is the reverse of w} \right\} L3={02i∣ i is an integer}L3=\left\{0^{2i} \mid \text{ i is an integer} \right\} L4={0i2∣ i is an integer}L4= \left\{ 0^{i^2} \mid \text{ i is an integer} \right\} Which of the languages are regular?
Official PYQ2001Theory of ComputationRegular Expressions and Finite AutomataMCQ · 1 mark
Consider a DFA over Σ={a,b}\Sigma=\{a,b\} accepting all strings which have number of a's divisible by 66 and number of bb's divisible by 88. What is the minimum number of states that the DFA will have?
Official PYQ2001Theory of ComputationRegular Expressions and Finite AutomataMCQ · 1 mark
Given an arbitrary non-deterministic finite automaton (NFA) with NN states, the maximum number of states in an equivalent minimized DFA at least
Official PYQ2001Theory of ComputationContext-free Grammars and Push-down AutomataMCQ · 1 mark
Which of the following statements is true?
Official PYQ2001Theory of ComputationRegular and Context-free LanguagesMCQ · 1 mark
Consider the following two statements: S1:{02n∣n≥1}S_1: \left\{ 0^{2n} \mid n \geq 1 \right\} is a regular language S2:{0m1n0m+n∣m≥1 and n≥1}S_2: \left\{0^m1^n0^{m+n} \mid m \geq 1 \text{ and } n \geq 1 \right\} is a regular language Which of the following statement is correct?
Official PYQ2000Theory of ComputationUndecidabilityMCQ · 1 mark
Consider the following decision problems: (P1):(P1): Does a given finite state machine accept a given string? (P2):(P2): Does a given context free grammar generate an infinite number of strings? Which of the following statements is true?
Official PYQ2000Theory of ComputationRegular and Context-free LanguagesMCQ · 1 mark
What can be said about a regular language LL over {a}\{ a \} whose minimal finite state automaton has two states?
Official PYQ2000Theory of ComputationRegular Expressions and Finite AutomataMCQ · 1 mark
Let SS and TT be languages over Σ={a,b}\Sigma=\{a,b\} represented by the regular expressions (a+b∗)∗(a+b^*)^* and (a+b)∗(a+b)^*, respectively. Which of the following is true?
Official PYQ2000Theory of ComputationRegular and Context-free LanguagesMCQ · 1 mark
Let LL denote the languages generated by the grammar S→0S0∣00S \to 0S0 \mid 00. Which of the following is TRUE?
Official PYQ1999Theory of ComputationRegular and Context-free LanguagesMSQ · 1 mark
If L1L1 is context free language and L2L2 is a regular language which of the following is/are false?
Official PYQ1999Theory of ComputationContext-free Grammars and Push-down AutomataMCQ · 1 mark
Context-free languages are closed under:
Official PYQ1999Theory of ComputationRegular Expressions and Finite AutomataMCQ · 1 mark
Consider the regular expression (0+1)(0+1)…N(0 + 1) (0+1) \dots N times. The minimum state finite automaton that recognizes the language represented by this regular expression contains
Official PYQ1999Theory of ComputationContext-free Grammars and Push-down AutomataMCQ · 1 mark
Let L1L_1 be the set of all languages accepted by a PDA by final state and L2L_2 the set of all languages accepted by empty stack. Which of the following is true?
Official PYQ1998Theory of ComputationRegular and Context-free LanguagesMCQ · 1 mark
Which of the following statements is false?
Official PYQ1998Theory of ComputationRegular Expressions and Finite AutomataMCQ · 1 mark
Let LL be the set of all binary strings whose last two symbols are the same. The number of states in the minimal state deterministic finite state automaton accepting LL is
Official PYQ1998Theory of ComputationRegular Expressions and Finite AutomataMSQ · 1 mark
The string 11011101 does not belong to the set represented by
Official PYQ1998Theory of ComputationRegular Expressions and Finite AutomataMCQ · 1 mark
Regarding the power of recognition of languages, which of the following statements is false?
Official PYQ1998Theory of ComputationRegular Expressions and Finite AutomataMCQ · 1 mark
Which of the following set can be recognized by a Deterministic Finite state Automaton?
Official PYQ1998Theory of ComputationRegular Expressions and Finite AutomataMCQ · 1 mark
If the regular set AA is represented by A=(01+1)∗A = (01 + 1)^* and the regular set BB is represented by B=((01)∗1∗)∗B = \left(\left(01\right)^*1^*\right)^*, which of the following is true?
Official PYQ1997Theory of ComputationContext-free Grammars and Push-down AutomataMCQ · 1 mark
Which of the following languages over {a,b,c}\left\{a,b,c\right\} is accepted by a deterministic pushdown automata? Note: wRw^R is the string obtained by reversing ′w′'w'.