Can anyone help me with this question: I know i asked a similar question not a while ago but i'm not able to understand how its possible. If anyone could give me a lot of examples instead of an answer.
I need to find the regular expression for this language: L=all words that have 00 or 11 but not both.
Thank you!
Here is my hint. Build a finite state machine to accept this language. So we start at $q_{0}$. If we read in a $0$, go to state $q_{1}$. Otherwise, go to state $q_{2}$.
At $q_{1}$, if we read in a $1$, go to $q_{0}$. Otherwise, go to $q_{3}$. From $q_{3}$, the idea is that if you read in a $11$, reject. So you can build the state transitions from there. The idea is similar branching out from $q_{2}$, except we check if we've read in a $11$, then check that we don't read in a $00$.
Then you can use a method to convert a FSM to a regular expression, using something like state reduction or the Brzozowski Algebraic Method.