GATE 2009
February 10, 2024ICT
February 10, 2024GATE 2009
| Question 15 |
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)*?
| The set of all strings containing the substring 00.
| |
| The set of all strings containing at most two 0’s. | |
| The set of all strings containing at least two 0’s. | |
| The set of all strings that begin and end with either 0 or 1. |
Question 15 Explanation:
Option A is false, as the regular expression generates string “010” which doesn’t have “00” as substring. Option B is false, as we can have the string “000” from the given regular expression, which has more than two 0’s. Option D is false, as we cannot generate the string “01” from the given regular expression and according to option D, string “01” must be generated by regular expression, which clearly shows option D is not correct language as per regular expression.
Correct Answer: C
Question 15 Explanation:
Option A is false, as the regular expression generates string “010” which doesn’t have “00” as substring. Option B is false, as we can have the string “000” from the given regular expression, which has more than two 0’s. Option D is false, as we cannot generate the string “01” from the given regular expression and according to option D, string “01” must be generated by regular expression, which clearly shows option D is not correct language as per regular expression.
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