DFA Machine Simulator

Language that accepts binary strings containing 00 or 11.

L = {xyyz | x,z ∈ {0,1}*, y ∈ {0,1}}

DFA Diagram

q3 is the accepting state
0 1 1 0 1 0 0,1
q0start
q1last symbol = 0
q2last symbol = 1
q3found 00 or 11

Test a String

Only symbols 0 and 1 are allowed.
Result will appear here.

Transition Table

Current State Input 0 Input 1
q0q1q2
q1q3q2
q2q1q3
q3q3q3

Step-by-Step Trace

No trace yet. Click Analyze String.
Easy explanation: The machine only needs to remember the previous symbol. If the previous symbol and current symbol are the same, it means the string contains 00 or 11, so the machine moves to q3 and accepts.