## MCQs TOC|UGC-NET|GATE|Computer Science

112. | Given the production rules of agrammar G1 as S1 ? AB | aaB A ? a | Aa B ? b and the production rules of a grammar G2 as S2 ? aS2bS2 | bS2aS2 | ? Which of the following is correct statement ? |

A. | G1 is ambiguous and G2 is not ambiguous. |

B. | G1 is ambiguous and G2 is ambiguous. |

C. | G1 is not ambiguous and G2 is ambiguous. |

D. | G1 is not ambiguous and G2 is not ambiguous. |

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113. | Given a grammar : S1 ? Sc, S ?SA | A, A ? aSb | ab, there is a rightmost derivation S1 ? Sc ?SAC ? SaSbc Thus, SaSbc is a right sentential form, and its handle is |

A. | SaS |

B. | bc |

C. | Sbc |

D. | aSb |

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Explanation | |

114. | Given L1=L(a*baa*) and L2=L(ab*). The regular expression corresponding to language L3 = L1/L2 (right quotient) is given by |

A. | a*b |

B. | a*baa* |

C. | a*ba* |

D. | None of the above |

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Explanation | |

115. | Given the following expressions of a grammar E -> E * F / F + E / F F -> F – F / id Which of the following is true ? |

A. | * has higher precedence than + |

B. | – has higher precedence than * |

C. | + and – have same precedence |

D. | + has higher precedence than * |

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116. | Which of the following is true while converting CFG to LL(I)grammar? |

A. | Remove left recursion alone |

B. | Factoring grammar alone |

C. | Both of the above |

D. | None of the above |

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117. | Let L be a set accepted by a nondeterministic finite automaton. The number of states in non-deterministic finite automaton is |Q|. The maximum number of states in equivalent finite automaton that accepts L is |

A. | |Q| |

B. | 2|Q| |

C. | 2 raise to power |Q| – 1 |

D. | 2 raise to power |Q| |

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Explanation | |

118. | Which is not the correct statement ? |

A. | The class of regular sets is closed under homomorphisms. |

B. | The class of regular sets is not closed under inverse homomorphisms. |

C. | The class of regular sets is closed under quotient. |

D. | The class of regular sets is closed under substitution. |

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119. | The grammar ‘G1’ S -> OSO| ISI | 0|1|? and the grammar ‘G2’ is S -> as |asb| X, X -> Xa | a. Which is the correct statement ? |

A. | G1 is ambiguous, G2 is unambiguous |

B. | G1 is unambiguous, G2 is ambiguous |

C. | Both G1 and G2 are ambiguous |

D. | Both G1 and G2 are unambiguous |

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Explanation | |

120. | The statements s1 and s2 are given as : s1 : Context sensitive languages are closed under intersection, concatenation, substitution and inverse homomorphism. s2 : Context free languages are closed under complementation, substitution and homomorphism. Which of the following is correct statement ? |

A. | Both s1 and s2 are correct. |

B. | s1 is correct and s2 is not correct. |

C. | s1 is not correct and s2 is correct. |

D. | Both s1 and s2 are not correct. |

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Explanation | |

121. | Which of the following regular expression identities are true ? |

A. | (r + s)* = r* s* |

B. | (r + s)* = r* + s* |

C. | (r + s)* = (r*s*)* |

D. | r* s* = r* + s* |

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Explanation |

Author Does Not claim of any answer these answers are as per expert opinion