Prerequisite – Finite Automata
1. DFA :
DFA refers to Deterministic Finite Automaton. A Finite Automata(FA) is said to be deterministic, if corresponding to an input symbol, there is single resultant state i.e. there is only one transition.
A deterministic finite automata is set of five tuples and represented as,
Q: A non empty finite set of states present in the finite control(qo, q1, q2, …).
Σ: A non empty finite set of input symbols.
δ: It is a transition function that takes two arguments, a state and an input symbol, it returns a single state.
qo: It is starting state, one of the state in Q.
F: It is non-empty set of final states/ accepting states from the set belonging to Q.
2. NFA :
NFA refers to Nondeterministic Finite Automaton. A Finite Automata(FA) is said to be non deterministic, if there is more than one possible transition from one state on the same input symbol.
A non deterministic finite automata is also set of five tuples and represented as,
Q: A set of non empty finite states.
Σ: A set of non empty finite input symbols.
δ: It is a transition function that takes a state from Q and an input symbol from and returns a subset of Q.
qo: Initial state of NFA and member of Q.
F: A non-empty set of final states and member of Q.
Difference between DFA and NFA :
|1||DFA stands for Deterministic Finite Automata.||NFA stands for Nondeterministic Finite Automata.|
|2||For each symbolic representation of the alphabet, there is only one state transition in DFA.||No need to specify how does the NFA react according to some symbol.|
|3||DFA cannot use Empty String transition.||NFA can use Empty String transition.|
|4||DFA can be understood as one machine.||NFA can be understood as multiple little machines computing at the same time.|
|5||In DFA, the next possible state is distinctly set.||In NFA, each pair of state and input symbol can have many possible next states.|
|6||DFA is more difficult to construct.||NFA is easier to construct.|
|7||DFA rejects the string in case it terminates in a state that is different from the accepting state.||NFA rejects the string in the event of all branches dying or refusing the string.|
|8||Time needed for executing an input string is less.||Time needed for executing an input string is more.|
|9||All DFA are NFA.||Not all NFA are DFA.|
|10||DFA requires more space.||NFA requires less space then DFA.|
Don’t stop now and take your learning to the next level. Learn all the important concepts of Data Structures and Algorithms with the help of the most trusted course: DSA Self Paced. Become industry ready at a student-friendly price.
- Difference Between Blu-Ray and DVD
- Difference between ELT and ETL
- Difference between TCP and RTP
- What is the difference between GUI and CUI?
- Difference Between Gi-Fi and Li-Fi
- Difference between RPC and RMI
- Difference between H.323 and SIP
- Difference between C and C#
- Difference between CLI and GUI
- Difference between 4NF and 5NF
- Difference between DDR 5 and DDR 3
- Difference Between SEO and SEM
- Difference between Blu-ray and DVD
- Difference between LAN and MAN
- Difference between PNG and GIF
- Difference between SDN and NFV
- Difference between PCI-E and PCI-X
- Difference between PCI and PCI-X
- Web 1.0, Web 2.0 and Web 3.0 with their difference
- Difference between T-SQL and PL-SQL
If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to email@example.com. See your article appearing on the GeeksforGeeks main page and help other Geeks.
Please Improve this article if you find anything incorrect by clicking on the "Improve Article" button below.