palindrome

e.g "ccddcc" in the string "abaccddccefe" I thought of a solution but it runs in O(n^2) time Algo 1: Steps: Its a brute force method Have 2 for loops for i = 1 to i less than array.length -1 for j=i+1 to j less than array.length This way you can get substring of every possible combination from the array Have a palindrome function which checks if a string is palindrome so for every substring (i,j) call this function, if it is a palindrome store it in a string variable If you find next palindrome substring and if it is greater than the current one, replace it with current one. Finally your

That was an interview question that I was unable to answer: How to check that a string is a palindrome using regular expressions? p.s. There is already a question " How to check if the given string is palindrome? " and it gives a lot of answers in different languages, but no answer that uses regular expressions. The answer to this question is that "it is impossible". More specifically, the interviewer is wondering if you paid attention in your computational theory class. In your computational theory class you learned about finite state machines. A finite state machine is composed of nodes and