Doubt

Question

The number of unique strings in L((a+b)* a(b+ba)* ) of length less than four is _____

Comments

11 ???

Answer 1

L= 0 => 0(No string possible)

L=1 => 1 {a}

L=2 => 3 {aa, ba, ab}

L=3 => 7 {aaa, aba, baa, bba, bab, aab, abb}

Therefore total =0+1+3+7=11

Answer 2

0 length 0

1 length =1 a

2 length = 3 aa,ba,ab

3 length = 7 aaa,aba,baa,aab,aba,bab

total 11

Comments

Bro, you cannot generate length 0 strings from this language as minimum 1 'a' has to be there.

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Thanks