Skip to content
Related Articles

Related Articles

Improve Article
Save Article
Like Article

GATE | GATE-CS-2009 | Question 14

  • Last Updated : 22 Nov, 2021

Which one of the following languages over the alphabet {0,1} is described by the regular expression: (0+1)*0(0+1)*0(0+1)* ?
(A) The set of all strings containing the substring 00.
(B) The set of all strings containing at most two 0’s.
(C) The set of all strings containing at least two 0’s.
(D) The set of all strings that begin and end with either 0 or 1.


Answer: (C)

Explanation: The regular expression has two 0′s surrounded by (0+1)* which means accepted strings must have at least 2 0′s.

The least possible string is ε 0 ε 0 ε = 00

Attention reader! Don’t stop learning now.  Practice GATE exam well before the actual exam with the subject-wise and overall quizzes available in GATE Test Series Course.

Learn all GATE CS concepts with Free Live Classes on our youtube channel.

The set of strings accepted is = { 00, 000, 100, 0010, 0000, 00100, 1001001,…..}

We can see from the set of accepted strings that all of the have at least two zeros which is the least possible string.

So option (C) is correct.

Quiz of this Question

My Personal Notes arrow_drop_up
Recommended Articles
Page :

Start Your Coding Journey Now!