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Consider the following grammar: <S> ? <A> a <B> b <A> ? <A> b | b <B> ? a <B> |

ID: 3558182 • Letter: C

Question

Consider the following grammar:

<S> ? <A> a <B> b
<A> ? <A> b | b
<B> ? a <B> | a

Which of the following sentences are in the language generated by this grammar?

baab

bbbab

bbaaaaa

bbaab

Consider the following grammar:

<S> ? a <S> c <B> | <A> | b
<A> ? c <A> | c
<B> ? d | <A>

Which of the following sentences are in the language generated by this grammar?

abcd

acccbd

acccbcc

acd

accc

a.

baab

b.

bbbab

c.

bbaaaaa

d.

bbaab

Explanation / Answer

1) <A> will generate one or more consecutive b's
<B> will generate one or more consecutive a's
  
So <A> a <B> b will generate
   One or more b's followed by One a followed by One or more a's followed by a b   which is the same as
   One or more b's followed by Two a's followed by a b
  
Which matches a and d

2)   <A> generates one or more c's
   <B> will generate either One d or a string of one or more c's
  
   So S will generate
    a <S> c   {d | c's} | c's | b
  
   which matches a and e

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