How to write this automaton

Question

I am trying to solve some problems in An Introduction to Formal Languages and Automata, by Peter Linz. In Section 2.1 (Deterministic Finite Acceptors), I cannot write the automaton and need help to solve it.

Question 17-(f), Chapter 2:

L = {w : |na(W) - nb(W)| % 3 < 2}

na is the number of a characters in the word, nb is the number of b characters in the word.

I have solution but I don't know how to draw it here.

[Find the regular expression for the language on `E = {a,b}`](http://stackoverflow.com/questions/19214574/find-the-regular-expression-for-the-language-on-e-a-b) — Grijesh Chauhan, Oct 26 '13 at 13:07

score 0 · Answer 1 · answered Jan 10 '19 at 00:00

0

So we have 3 states: R0, R1, R2, which mean the remainders of the division by 3. Then we have our automaton with R0 the start state:

R0(a) -> R1
R0(b) -> R2
R1(a) -> R2
R1(b) -> R0
R2(a) -> R0
R2(b) -> R1

R0 and R1 are accepting states.

answered Jan 10 '19 at 00:00

lunesco

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How to write this automaton

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