Problem
1. Explain how you would modify the nondeterministic machine to handle "don't-care" characters.
2. How many different patterns can be described by a regular expression with M or operators and no closure operators?
3. Modify match to handle regular expressions with the not function and "don't-care" characters.
4. Show how to construct a pattern description of length M and a text string of length N for which the running time of match is as large as possible.