symbols and make transitions so that the needed information is kept track
of.
Chapter 2
Section 2.1
2. (c) Break it into three cases each with an accepting state: no a’s, one a,
two a’s, three a’s. A fourth a will then send the dfa into a nonaccepting
trap state. A solution:
5. (a) The first six symbols are checked. If they are not correct, the string is
rejected. If the prefix is correct, we keep track of the last two symbols
read, putting the dfa in an accepting state if the suffix is bb.