Regex

It is in week 11 now! Almost finish this course!

Now we are learning Regex and NFSA and DFSA. The last assignment is coming and it is about time comlexity and FSAs.

Most of the lecture material was not difficult to understand, but I was kind of confused by the difference between DFSA and NFSA. What I did this time was to look up definitions on the textbook. On the textbook, it said:
A deterministic finite state automaton (DFSA) is a mathematical model of a machine which, given any string input x, accepts or rejects x. The automaton has a finite set of states. including a designated initial state and a designated set of accepting states. While the definition of NFSA was that: In a DFSA, a given state and current input symbol uniquely determine the next state of the automaton.

To my understanding, the difference is that: in DFSA, the state only depends on the input, but in NFSA, the state depends on both the current input and also the given state.

BTW, I like drawing NFSA or DFSA, it was much more interesting than just to prove something using Induction or prove the correctness of a funciton.