Difference Between NFA and DFA

The DFA stands for deterministic finite automata. If any machine reads an input string one at a time then any finite automata is called deterministic finite automata. The DFA is also known as the uniqueness of computation and has a single path for input from the current state to the next state. It is a set of five tuples such as:

M = (Q, Σ, δ, q0, F)


1. Q is a finite set of states.

2. Σ is an alphabet, and the DFA processes strings over Σ.

3. δ: Q × Σ → Q is the transition function. • δ defines the label on each edge.

4. q0 ∈ Q is the start state (or initial state).

5. F ⊆ Q is the set of accepted states (or final states).

What is NFA?

The full form of NFA is Non- deterministic finite automata. When there are multiple paths for specific input from current state to next state then it is called Non- deterministic finite automata.

Difference Between DFA and NFA

1 The full form of DFA is Deterministic Finite Automata. The full form of NFA is Nondeterministic Finite Automata (NFA).
2 It is not competent in handling an Empty String transition. It is competent to handle an empty string transition.
3 In DFA, only a sole state transition can be accomplished for each symbolic representation of the characters. In NFA, no particulars are required from the users.
4 It can be defined as one machine. Multiple machines execute computational tasks at the same time.
5 In DFA, backtracking is allowed. In NFA, backtracking is not allowed.
6 In DFA, empty string transitions are not noticed. It allows empty string transition.
7 It is tough to construct a DFA. It is easy to construct a NFA.
8 It needs more space. It needs less space.
9 The complete time needed for managing any input string in DFA is shorter than NFA. The complete time needed for managing any input string in NFA is larger than DFA.
10 All DFA are considered as NFA. All NFA are not considered as DFA.

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