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GATE 2014 [Set-3]
April 4, 2025GATE 2014 [Set-3]
April 4, 2025GATE 2014 [Set-3]
| Question 25 |
The length of the shortest string NOT in the language (over Σ = {a b,} of the following regular is expression is ______________.
a*b*(ba)*a*
| 3 | |
| 4 | |
| 5 | |
| 6 |
Question 25 Explanation:
The regular expression generate all the strings of length 0 , 1 and 2
{ϵ, a, b, aa, ab, ba, bb}
Let’s check all the string of length 3.
The given regular expression generates {aaa, aab, aba, abb, baa, bba, bbb}
But it doesn’t generate the string “bab”, hence the shortest string not generated by regular expression has length 3 (string “bab”).
{ϵ, a, b, aa, ab, ba, bb}
Let’s check all the string of length 3.
The given regular expression generates {aaa, aab, aba, abb, baa, bba, bbb}
But it doesn’t generate the string “bab”, hence the shortest string not generated by regular expression has length 3 (string “bab”).
Correct Answer: A
Question 25 Explanation:
The regular expression generate all the strings of length 0 , 1 and 2
{ϵ, a, b, aa, ab, ba, bb}
Let’s check all the string of length 3.
The given regular expression generates {aaa, aab, aba, abb, baa, bba, bbb}
But it doesn’t generate the string “bab”, hence the shortest string not generated by regular expression has length 3 (string “bab”).
{ϵ, a, b, aa, ab, ba, bb}
Let’s check all the string of length 3.
The given regular expression generates {aaa, aab, aba, abb, baa, bba, bbb}
But it doesn’t generate the string “bab”, hence the shortest string not generated by regular expression has length 3 (string “bab”).