Introduction to Computer Theory

Question

Construct a PDA for the language of all those strings in which the number of $b 's$ is double the number of $a 's$. $a$ and $b$ can occur in any order. For example:

$L=\{\text{^}, abb, bab, bba, aabbbb, ababbb, abbbabb, abbbab, abbba, ...... \}$

Comments

how will it accept bab

---

1) (b, z₀ , bz₀)

2) (a,b , ϵ)

3) ( ϵ , z₀ , az₀)

4) (b,a , ϵ )

5) ( ϵ , z₀, z₀)

---

No.it is PDA.More precisely DPDA.Read definition of PDA first from a standard textbook(peter linz/sipser).