Welcome to Finite State Automaton Challenges 2. It is the second episode of Finite State Automation Challenges. In this game, you will play with the simplest automaton model, Finite State Automaton, and use it to cope with 80 challenges from variants of the previous episode, character string manipulation, computer science, and mathematics.

If you are unfamiliar with Finite State Automaton, we highly recommend playing our first game (Finite State Automation Challenges) or learning it online in advance.

The criterion for judging whether it is suitable to play this game is whether you can answer the following question:

The above picture shows a finite-state automaton. The first state with two colors denotes that it is both a beginning and accepting state. So, what is the pattern of strings accepted by this automaton?

Two Major Updates

We're making the game even more challenging and fun by introducing two major updates:

A state can be both beginning and accepting.
Some challenges require you to create a deterministic automaton (thanks for the suggestions from players), which means:
- There is at most one begin state.
- Empty edges are not allowed, i.e., each edge must contain at least one character.
- For a character, a state can transit to at most one state, i.e., no conflict edges.

Besides, we add red spots to denote each challenge's difficulty so that you can take your own route through the challenges.