build a finite automata that accept only those words that do not end with ba, with alphabet {a,b}. how to solve this question. how to know that what input we take. plz help me in this subject

Question

anonymous · Answer

I'm not very familiar with finite automata terminology and notation, so forgive me for that, but I do know about the underlying concepts since they're very similar to FSMs.

It might be easier to solve the problem by changing it slightly. Start by designing an automata that will only accept words that do end with 'ba'. When you've finished that automata, change every accepting state into a non-accepting state and every non-accepting state into an accepting state.

To design an automata that will accept words ending in 'ba', you will need states for 'I've seen a b' and 'I've seen a b followed by an a' (which would be the accept state) and 'I've not seen a b yet'. Try to figure out the state transitions yourself.