I am attempting to draw the DFA of this problem but I'm kind of stuck. In another post I saw that the DFA should have 10 states. I'm finding it hard to even understand the question, is the input to the DFA the full string so for example 1001 or is it multiple inputs of length 3 in this example 100 and then 001. I've made multiple DFA's now but they all seem incorrect to me. Below is my latest attempt which doesn't seem to work for me. Since when trying the string 1001 it goes to an accepting state but the last 1 puts it back into a non accepting state. I'm really struggling with checking for every substring of length 3 since you leave the final state when you have a length which is not a multiple of 3, but it should still be accepted. How would I make a DFA that accepts strings of minimal length 3 but then also of length 4 which satisfies these conditions? (I know the DFA is not yet fully finished) I have created a dead state for whenever a string has 2 1's within a substring of length 3.
EDIT: The last DFA is correct :)