1 votes 1 votes Build an DFA that accepts a and b as an input and contain words that does not begin and end with double letters. Theory of Computation theory-of-computation finite-automata + – hashir inayat asked Jul 20, 2017 hashir inayat 809 views answer comment Share Follow See all 9 Comments See all 9 9 Comments reply Shubhanshu commented Jul 20, 2017 reply Follow Share Is double letter mean here same char?? 0 votes 0 votes hashir inayat commented Jul 20, 2017 reply Follow Share Yes it is a same char 0 votes 0 votes akash.dinkar12 commented Jul 21, 2017 reply Follow Share if i m getting ur question then it might be ur answer... 0 votes 0 votes hashir inayat commented Jul 21, 2017 reply Follow Share regular expression plzz 0 votes 0 votes Shubhanshu commented Jul 21, 2017 reply Follow Share Its Regular Exp:- a(a+bb*a)*bb* + b(b+aa*b)*a 0 votes 0 votes joshi_nitish commented Jul 21, 2017 i edited by joshi_nitish Jul 21, 2017 reply Follow Share i think double letter means 'aa' or 'bb', now string not begining and ending with double letters will not start and end with 'aa' or 'bb'....so dfa in this case will be, 0 votes 0 votes Shubhanshu commented Jul 21, 2017 reply Follow Share it will not accept abbbbba which is nor starting with aa or bb and neither ending with aa or bb. 0 votes 0 votes joshi_nitish commented Jul 21, 2017 reply Follow Share ohh sorry, i was in hurry, i hadnt checked it, now corrected.... 0 votes 0 votes Shubhanshu commented Jul 21, 2017 reply Follow Share It seems correct now.!! 0 votes 0 votes Please log in or register to add a comment.