Question :
Suppose that during document indexing we are interested in identifying all dates in the format mm/dd/yyyy, where mm is a 2 digit string representing the month (ranging from 01 through 12), dd is a 2-digit string representing the day (01-31), and yyyy are 4 digits representing the year.
Furthermore, we are only interested in the years between 1990 and 2019.
Example: 02/30/2012. Construct a Finite State Automata that exactly recognizes date tokens as described above.
Notes: You do not need to match the month with the correct number of days.
You may assume that dig is a special token representing all digits (0-9). Also, specify a regular expression that corresponds to the finite automata for this language.