Theory of Computation Solved MCQ - Part 2

Given the language L-{ab, aa, baa}, which of the following strings are in L*? 1) abaabaaabaa 2) aaaabaaaa 3) baaaaabaaaab 4) b...

Given the language L-{ab, aa, baa}, which of the following strings are in L*? 1) abaabaaabaa 2) aaaabaaaa 3) baaaaabaaaab 4) baaaaabaa 1,2 and 3 2,3 and 4 1,2 and 4 1,3 and 4       _____________________________________________________________________________________

Push down machine represents Type 0 Grammar Type 1 grammar Type-2 grammar Type-3 grammar       _____________________________________________________________________________________

The behavior of a NFA can be stimulated by DFA  always sometimes never depend on NFA       _____________________________________________________________________________________

Both statements S1 and S2 are incorrect. S1 is incorrect and S2 is correct. S1 is correct and S2 is incorrect. Both statements S1 and S2 are correct.       _____________________________________________________________________________________

A B C D       _____________________________________________________________________________________

Which of the following is not primitive recursive but partially recursive?  Carnot function Rieman function Bounded function Ackermann function       _____________________________________________________________________________________

Consider the following grammar. S ::= AB A ::= a A ::= BaB B ::= bbA Which of the following is false? No string produced by the grammar has four consecutive b s No string produced by the grammar has three consecutive a s No string produced by the grammar has an odd number of consecutive b s The length of every string produced by the grammar is even.       _____________________________________________________________________________________

Set of regular languages over a given alphabet set,is not closed under  Union Complementation Intersection None of the above       _____________________________________________________________________________________

Consider the regular expression (a + b) (a + b) … (a + b) (n-times). The minimum number of states in finite automaton that recognizes the language represented by this regular expression contains n states n + 1 states n + 2 states 2n states       _____________________________________________________________________________________

LL grammar for the language L = {an bm cn+m | m=0, n=0} is A B C D       _____________________________________________________________________________________

The logic of pumping lemma is a good example of  The pigeon hole principle Divide and conquer method Iteration Recursion       _____________________________________________________________________________________

If every string of a language can be determined whether it is legal or illegal in finite time the language is called  Decidable Undecidable Interpretive Non deterministic       _____________________________________________________________________________________

Context free language can be recognized by  Finite State Automaton Linear bounded automaton Pushdown automaton Both B and C       _____________________________________________________________________________________

Fred created a new automaton model which is a push down automaton but with two stacks and the added ability of having commands which do not read input tape but which can pop from one stack and push into the other.This new automaton can recognize (choose strongest result) Context free language Context sensitive language Regular language Languages recognizable by Turing machine       _____________________________________________________________________________________

Given the following productions of a grammar : The language corresponding to the given grammar is a set of even number of a s. The language corresponding to the given grammar is a set of odd number of a s. The language corresponding to the given grammar is a set of even number of a’s followed by odd number of b s. The language corresponding to the given grammar is a set of odd number of a’s followed by even number of b s.       _____________________________________________________________________________________

Consider the set of strings on {0,1} in which, every substring of 3 symbols has at most two zeros. For example, 001110 and 011001 are in the language, but 100010 is not. All strings of length less than 3 are also in the language. A partially completed DFA that accepts this language is shown below. A B C D       _____________________________________________________________________________________

A B C D       _____________________________________________________________________________________

The regular expression for the following DFA ab*(b + aa*b)* a*b(b + aa*b)* a*b(b* + aa*b) a*b(b * + aa*b)*       _____________________________________________________________________________________

FSM can recognize  Any grammar Only CFG Any unambiguous grammar Only regular grammar       _____________________________________________________________________________________

Assume statements S1 and S2 defined as : S1 : L2-L1 is recursive enumerable where L1 and L2 are recursive and recursive enumerable respectively. S2 : The set of all Turing machines is countable.  Which of the following is true ? S1 is correct and S2 is not correct. Both S1 and S2 are correct. Both S1 and S2 are not correct. S1 is not correct and S2 is correct.       _____________________________________________________________________________________

Which of the following is the most general phase structured grammar ? Regular Context-sensitive Context free None of the above       _____________________________________________________________________________________

A FSM can be used to add how many given integers?  1 3 4 5       _____________________________________________________________________________________

The language accepted by the nondeterministic pushdown automaton L(abb*a) {a} U L(abb*a) L(ab*a) {a} U L(ab*a)       _____________________________________________________________________________________

Consider the following statements : I. Recursive languages are closed under complementation. II. Recursively enumerable languages are closed under union. III. Recursively enumerable languages are closed under complementation. Which of the above statements are true ? I only I and II I and III I and III       _____________________________________________________________________________________

6 Files F1,F2,F3,F4,F5 and F6 have 100,200,50,80,120,150 records repectively. In what order should they be sorted so as to optimize activity? Assume each file is accessed with the same frequency. F3,F4,F1,F5,F6,F2 F2,F6,F5,F1,F4,F3 F1,F2,F3,F4,F5,F6 Ordering is immaterial as all files are accessed with the same frequency       _____________________________________________________________________________________

Following grammar S-> bS S -> b S -> aA A -> bA Type -3 grammar Type -2 grammar Type -1 grammar Type -0 grammar       _____________________________________________________________________________________

Which of the following problems are decidable? 1) Does a given program ever produce an output? 2) If L is context-free language, then, is ~L also context-free? 3) If L is regular language, then, is ~L also regular? 4) If L is recursive language, then, is ~L also recursive? 1,2,3,4 1,2 2,3,4 3,4       _____________________________________________________________________________________

The language L={ak bk|k>=1} is Type -3 Grammar Type -2 Grammar Type -1 Grammar Type -0 Grammar       _____________________________________________________________________________________

All strings having equal number of a and b can be recognized by  DFA NDFA PDA All of these       _____________________________________________________________________________________

The basic limitation of a FSM is that  It cannot remember arbitrary large amount of information It sometimes recognizes grammar that are not regular It sometimes fails to recognize grammars that are regular All of the above       _____________________________________________________________________________________

How many states can a process be in ? 2 3 4 5       _____________________________________________________________________________________

Which one of the following statement is false ? Context-free languages are closed under union Context-free languages are closed under concatenation Context-free languages are closed under intersection Context-free languages are closed under Kleene closure       _____________________________________________________________________________________

Given the language L = {ab, aa, baa}, which of the following strings are in L*? 1) abaabaaabaa 2) aaaabaaaa 3) baaaaabaaaab 4) baaaaabaa 1, 2 and 3 2, 3 and 4 1, 2 and 4 1, 3 and 4       _____________________________________________________________________________________

Which is not the correct statement(s) ? (i) Every context sensitive language is recursive. (ii) There is a recursive language that is not context sensitive. (i) is true, (ii) is false. (i) is true and (ii) is true. (i) is false, (ii) is false. (i) is false and (ii) is true.       _____________________________________________________________________________________

A formal grammar is a___________for rewriting strings.  Set of rules Set of functions Both A and B None of the above       _____________________________________________________________________________________

Finite automata are used for pattern matching in text editors for  Compiler lexical analysis Programming in localized application Both A and B None of the above       _____________________________________________________________________________________

Two finite states are equivalent if they  Have same number of states Have same number of edges Have same number of states and edges Recognize same set of tokens       _____________________________________________________________________________________

A PDM behaves like a TM when the number of auxiliary memory it has is  Zero One or more Two or more None of these       _____________________________________________________________________________________

Which of the following permanent database that has an entry for each terminal symbol ? Literal table Identifier table Terminal table Source table       _____________________________________________________________________________________

The language accepted by finite automata is  Context free Regular Non regular None of these       _____________________________________________________________________________________

The following CFG S®aB|bA, A®a|as|bAA, B®b|bs|aBB generates strings of terminals that have Odd number of a’s and odd number of b’s Even number of a’s and even number of b’s Equal number of a’s and b’s Not equal number of a’s and b’s       _____________________________________________________________________________________

An FSM can be used to add two given integers.This remark is  True False May be true None of the above       _____________________________________________________________________________________

Context free languages are not closed under  Union Concatenation Closure Iteration       _____________________________________________________________________________________

Given a Non-deterministic Finite Automation (NFA) with states p and r as initial and final states respectively and transition table as given below : The minimum number of states required in Deterministic Finite Automation (DFA) equivalent to NFA is 5 4 3 2       _____________________________________________________________________________________

Which of the following is most powerful?  DFA NDFA 2PDA DPDA       _____________________________________________________________________________________

Which of the following statements is/are FALSE? (1) For every non-deterministic Turing machine, there exists an equivalent deterministic Turing machine. (2) Turing recognizable languages are closed under union and complementation. (3) Turing decidable languages are closed under intersection and complementation (4) Turing recognizable languages are closed under union and intersection. 1 and 4 only 1 and 3 only 2 only 3 only       _____________________________________________________________________________________

G1 is ambiguous and G2 is not ambiguous. G1 is ambiguous and G2 is ambiguous. G1 is not ambiguous and G2 is ambiguous. G1 is not ambiguous and G2 is not ambiguous.       _____________________________________________________________________________________

Finite state machine___________recognize palindromes.  Can Cannot May May not       _____________________________________________________________________________________

Given L1=L(a*baa*) and L2=L(ab*). The regular expression corresponding to language L3 = L1/L2 (right quotient) is given by a*b a*baa* a*ba* None of the above       _____________________________________________________________________________________

If two finite state machines are equivalent they should have the same number of  States Edges States and edges None of these       _____________________________________________________________________________________