I'm trying to design a DFA in a 4 digit language, for example L(a,b,c,d) or L(1,2,3,4) that accepts strings with the last character being already repeated before.
Everyway im trying, i get so many transitions im literally lost in them...
So, for example, abbdb is accepted (because b is showed again at least 1 time) but abc is rejected since c (last char) never shows up more than 1 time.
I managed to make it work for a language with 2 DIGIT:
For example:
Which accepts for example aa or ababa but can't do for 4 DIGIT language.