Definition of DFA

Deterministic Finite Automata can be formally represented using five tuples(Q, Σ, δ, q0 F), where 

Q- finite non-empty set of states
Σ- finite non-empty set of input terminals
δ- transition function defined as a mapping
δ: Q ×E ->Q
q0 ∈ Q - is the initial state
F ∈ Q - is a set of final states

In this article, two instructions are given –

• DFA should have at least 1 a
• DFA should have exactly 2 b’s

This DFA should accept strings such as abb, bab, and bba.

Deterministic Finite Automata(DFA) is also known as Deterministic finite state automata(DSA). DFA is a Mathematical model of computation it is an abstract machine used to recognize patterns, it takes a string as input and changes its states accordingly when the desired terminal is found, then the transition occurs. At the time of transition, the automata can either move to the next state or stay in the same state.

It has two types of states:

1. ACCEPT(final state):A string is accepted means it reaches the final state.
2. REJECT(non-final state): A string is rejected means it does not reach the final state.