L=set of all bit strings with even number of 1's ...Regular Expression will be .

Question

Options are

a) (0*10*1)*

b) 0*(10*10*)

c) 0*(10*1)*0*

d) 0*(10*1)*10*

 

I have doubt in b and c.which one is correct and why.?

Answer 1

IT would be option c

Answer 2

Answer is C, Check for string 110 neither a) nor b) can express it, and since d) is clearly expressing strings containing odd number of 0's so option c is correct. Moreover, option b) is expressing strings containing only two 1's, in case you have not done a typo. ;)

Comments

Yes, you are right, I am sorry,I did not cared that we can only use one time.

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so none of the options are matchin

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Yeah! None of the options are matching for sure. Possibly there is some mistake in the question.

Answer 3

ans is None of the options are matching .

For A check with 110

For B and C check with 110011

for D this is pretty much obvious that it can support odd length also .

Comments

You are right..and if b) were  0*(10*10*)*..then it would be answer. 

Answer 4

clearly none of the answers actually match .try 110011 as already mentioned. .. I dont think ambiguous questions will be given in GATE.