Automata Interview Questions and Answers
Question - 51 : - What is the difference between the alphabet and an element of a set?
Answer - 51 : -
Alphabets is a set of letters nothing else but a set of strings (elements) can have more than one letters in one string.
Question - 52 : - Difference between Palindrome and Reverse function?
Answer - 52 : -
The language consisting of Λ and the strings s defined over Σ such that Rev(s)=s.It is to be denoted that the words of PALINDROME are called palindromes.
Reverse (w) = w
Example: Σ={a,b},
PALINDROME={Λ , a, b, aa, bb, aaa, aba, bab, bbb, …}
If a is a word in some language L, then reverse (a) is the same string of letters spelled backwards, called the reverse of a.
e.g
reverse (xxx) = xxx
reverse (623) = 326
reverse (140) = 041
Question - 53 : - Define Strings?
Answer - 53 : -
Concatenation of finite letters from the alphabet is called a string.
e.g If Σ= {a,b} then a language L can be defined asL = {a, abab, aaabb, ababababababababab,……………}
it’s mean all words with a’s more or equal to b’s
Question - 54 : - Define empty or null strings?
Answer - 54 : -
Concatenation of finite letters from the alphabet is called a string.Sometimes a string with no symbol at all is used, denoted by (Small Greek letter Lambda) λ or (Capital Greek letter Lambda) Λ, is called an empty string or null string.
Question - 55 : - Difference between string and word?
Answer - 55 : -
Any combination of letters of alphabet that follows rules of language is called a word.
A string is a finite sequence of symbols from an alphabet.
Question - 56 : - There are as many palindromes of length 2n as there are of length 2n-1, please explain?
Answer - 56 : -
If we try to create palindromes then middle elements (2 in even palindromes & 1 in odd palindrome) does not cause any change in no. of palindromesDefining the language PALINDROME, of length 2n and 2n-1 defined over S = {a,b}
e.g if we take n= 2 for 2n
Length (2n) = 4 and string can be written as
{aaaa, abba, baab, bbbb}
And if we take n = 2 for 2n-1
Length (2n-1) = 3 and string can be written as
{aaa, aba, bab, bbb}