Showing posts with label RGPV TOC PYQ. Show all posts
Showing posts with label RGPV TOC PYQ. Show all posts
NDFA accepting two consecutive a’s or two consecutive b's.
RGPV 2020
Construct a NDFA accepting all string in {a,b} with either two consecutive a’s or two consecutive b's.
Ans.
Grammar is ambiguous. S → aSbS|bSaS|∈
RGPV 2020
Show that the following grammar is ambiguous.
S → aSbS|bSaS|∈
Ans. For grammar to be ambiguous, there should be more than one parse tree for same string.
Above grammar can be written as
S → aSbS
S → bSaS
S → ∈
Lets generate a string 'abab'.
So, now parse tree for 'abab'.
Left most derivative parse tree 01
S → aSbS
S → a∈bS
S → a∈baSbS
S → a∈ba∈b∈
S → abab
S → aSbS
S → abSaSbS
S → ab∈aSbS
S → ab∈a∈bS
S → ab∈a∈b∈
S → abab
So there are more than 1 parse tree for same string, that means grammar is ambiguous.
leftmost and rightmost derivations
RGPV 2020
What are leftmost and rightmost derivations? Explain with suitable example ?
Construct Moore machine for Mealy machine
RGPV 2020
Construct Moore machine for the following Mealy machine.
Sol.
Transition table for above Mealy machine.
Present State |
Next State |
|||
Input = 0 |
Input = 1 |
|||
State |
Output |
State |
Output |
|
q0 |
q0 |
0 |
q1 |
1 |
q1 |
q2 |
2 |
q0 |
0 |
q2 |
q1 |
1 |
q2 |
2 |
Transition table for Moore machine from above Mealy machine transition table.
Present State |
Next State |
Output |
|
Input = 0 |
Input = 1 |
||
q0 |
q0 |
q1 |
0 |
q1 |
q2 |
q0 |
1 |
q2 |
q1 |
q2 |
2 |
Transition diagram for Moore machine fram above Moore machine transition table.
DFA end with 1 contain 00 | RGPV TOC draw
RGPV 2007
Q. Define deterministic finite automta. Draw DFA that accepts any string which ends with 1 or it ends with an even number of 0's following the last 1. Alphabets are {0,1}.
Ans. Some example strings = {1, 001, 01001, 011}
NFA to DFA | RGPV TOC
RGPV 2009
Q. Construct minimized DFA for the given NFA.
Or
Convert the following NFA into DFA.
Ans.
Transition table for given NFA
State |
Input |
|
a |
B |
|
è q0 |
q0, q1 |
q0 |
q1 |
q2 |
q1 |
q2 |
q3 |
q3 |
q3 |
- |
q2 |
Transition table for DFA from given NFA table
State |
Input |
|
a |
B |
|
è [q0] |
[q0, q1] |
[q0] |
[q0, q1] |
[q0, q1, q2] |
[q0, q1] |
[q0, q1, q2] |
[q0, q1, q2, q3] |
[q0, q1, q2] |
[q0, q1, q2, q3] |
[q0, q1, q2, q3] |
[q0, q1, q2, q3] |
[q0, q1, q2] |
[q0, q1, q2] |
[q0, q1, q2] |
Transition diagram for DFA from above DFA transition table
Moore to Mealy | RGPV TOC PYQ
RGPV 2009
Construct a Mealy mcahine which is equivalent to the Moore mchine given below.
Present State |
Next State |
Output |
|
a = 0 |
a = 1 |
||
q0 |
q1 |
q2 |
1 |
q1 |
q3 |
q2 |
0 |
q2 |
q2 |
q1 |
1 |
q3 |
q0 |
q3 |
1 |
Ans. Mealy machine
Present State |
Next State |
|||
a = 0 |
a = 1 |
|||
Next State |
Output |
Next State |
Output |
|
q0 |
q1 |
0 |
q2 |
1 |
q1 |
q3 |
1 |
q2 |
1 |
q2 |
q2 |
1 |
q1 |
0 |
q3 |
q0 |
1 |
q3 |
1 |
Mealy machine |
DFA accept even 0 and even 1 |RGPV TOC PYQ
RGPV 2011
Design FA which accepts even no. of 0's and even no. of 1's.
Or
RGPV 2010
Construct DFA ove input alphabet Σ = {0,1} to accept string which contains no. of 0 is even and no. of 1 is even.
Or
RGPV 2008
Construct DFA accepting set of all strings containing even no. of a's and even no. of b's over input alphabet {a,b}.
Ans. Some example strings = {00, 11, 0011, 0101, 0110}

Short note on automata | RGPV TOC PYQ
RGPV 2010
Q. Write short note on automata ?
Ans. An automaton is an abstract model of a digital computer.
Some types of automata :
- Finite-state machine.
- Pushdown automata.
- Turing machine
DFA ending with 00 start with 0 no epsilon | RGPV TOC PYQ
RGPV 2015
Q. Design DFA accepting the following languages over the alphabet {0, 1}- The set of all words ending in 00.
- The set of all words except ε.
- The set of all words that begin with 0.
Ans.
1. The set of all words ending with 00:
Some example strings = {00, 100, 000, 1000,0100,11100}
Regular expression = (0+1)*00
2. The set of all words except ε:
Some example strings = {0, 1, 00, 10, 01, 11, 000000, 11111}
Regular expression = (0+1)(0+1)*
3. The set of all words that begin with 0:
Some example strings = {0, 01, 00000, 0101010101}
Regular expression = 0(0+1)*
DFA ending with 101 | RGPV TOC PYQ
RGPV 2006
Q. Give DFA accepting the language over alphabet {0,1} such that all strings of 0 and 1 ending in 101.
Ans. Some example strings = {101, 10101, 01101, 00101, 111o1, 1101}
Regular expression = (0+1)*101
Minimum number of states required = 4
Construct DFA for a power n, n>=0 || RGPV TOC
RGPV 2009
Q. Construct DFA for anb | n>=0.
Ans. Some example strings = {ab, aab, aaab, aaaab}
Minimum number of states required = 2.
Construct FA divisible by 3 | RGPV TOC PYQ
RGPV 2010
Construct a finite automta that will accept those strings of a binary number that are divisible ny three.
or
RGPV 2009
construct DFA for binary integer divisible by 3
Ans. Some example strings = {0, 11, 110, 1001, 1100}
Minimum number of states required = 4

Construct DFA equivalent to NFA | RGPV TOC PYQ
RGPV 2014
Q. Construct DFA equivalent to the NFA
M = ({p, q, r, s}, {0, 1}, δ, p, {q, s})
Where δ is defined in the following table.
δ | 0 | 1 |
p | {q, s} | {q} |
q | {r} | {q, r} |
r | {s} | {p} |
s | - | {p} |
Ans.
State | 0 | 1 |
[p] | [q, s] | [q] |
[q] | [r] | [q, r] |
[q, s] | [r] | [q, r, p] |
[r] | [s] | [p] |
[q, r] | [r, s] | [q, r, p] |
[q, r, p] | [q, s, r] | [p, q, r] |
[s] | Φ | [p] |
[r, s] | [s] | [p] |
[q, s, r] | [r, s] | [p, q, r] |
RGPV TOC design finite automata problems
RGPV 2008
Prob 01: Designa FA which accepts set of strings containing four 1's in every string over alphabet ∑ = {0, 1}.
Ans. Some example strings = {1111,0110101, 001100110}
RGPV 2016
Prob 02. Design NFA that accepts all strings with at most 3 a's.
Ans. Some example strings = {aaa, baba, a, ab}
RGPV 2014
Prob 03: Construct a finite automata for the language {0n | n mod 3 = 2, n>=0}
Ans. Some example strings = {00,00000,00000000}
RGPV 2016
Design a NFA for {cbabn | n>=0}
Ans. Some example strings = {cba, cbab, cbabb, cbabbb}
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