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regular expression to DFA

Posted on 2008-09-30
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How do you draw this in a DFA?

w | each 1 in w is immediately preceded and immediately followed by a 0
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Question by:kuntilanak
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yans earned 2000 total points
ID: 22610815
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Author Comment

by:kuntilanak
ID: 22610840
how does :

 b* + b*a(ba)*

satisfies my question, please explain
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Expert Comment

by:yans
ID: 22610882
The question deals with regular expression. b* + b*a(ba)* is a regular expression representation and the solution demostrates how to draw it.

If you may check some reference on reading regular expression syntax.

http://en.wikipedia.org/wiki/Regular_expression
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Author Comment

by:kuntilanak
ID: 22610905
I don't understand how b* + b*a(ba)* represents each 1 in w is immediately preceded and immediately followed by a 0
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Author Comment

by:kuntilanak
ID: 22610911
if 1 is equal to b here, then one possibility that regex gives me is 1* which can be an empty string and it is not followed immediately by a 0.
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Expert Comment

by:ozo
ID: 22611143
0* (0 1 0 0*)*
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Author Comment

by:kuntilanak
ID: 22611151
ozo can you please explain that a bit
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Author Comment

by:kuntilanak
ID: 22616778

on the picture below, the start state is when given an input b, what if the input at the start state is a? It doesn't covers that..
dfa.png
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