1. Title
The state transition of a finite automata DFA is as shown in the figure below (0 is out of state, 4 is final state), then the DFA can recognize ____.
A aaab
B abab
C bbba
D abba
2. Theory
The finite automata DFA seems to be a very high-end concept. In fact, this is a sub-question. As long as you simply understand how to read the picture, you can easily make it.
Looking at the picture above, there is an arrow from 0 to 1, so it is a;
from 0 to 1 to 3, there is an arrow, so it is aa.
From 3 to 3, there is an arrow pointing to itself, indicating a cycle, then there can be infinite a or b generated in this place.
There are arrows from 3 to 4, so it is b.
3. Analysis
Looking at the whole, no matter which path you take, the beginning must be aa (going 0-1-3) or bb (going 0-2-3), and the end must be b. The only option that fits is A, choose A.