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TOPIC : REGULAR EXPRESSIONS,

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1.One of the following Regular Expressions is not the same as others. Which one?

 

A. (a* + b*a*)*            B. (a*b* + b*a*)* (a*b*)*

 

C. ((ab)* + a*)*           D. (a + b)* a*b*a*b*
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3 Answers

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It should be C. It does not generate strings having 2 consecutive b's including b alone. Rest are equivalent to (a+b)*
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Ans is c.

take any string starting with b. Options a,b,d satisfied this but Option c is not able to satisfy .
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