I have been confusing a question for 2 days. I think I solved the question, but I don't know if it's true. Can you help me tell me I did it right or wrong?
The question is ;
Write a context-free grammar for the language $$L = \{ w \mid \text{the first, middle and last symbols of $w$ are the same}\}$$ defined on the alphabet $\{0,1\}$.
I found the answer like this.
$S \to 0A0 \mid 1A1$
$A \to 0S0 \mid 1S1$
Thank you from now...
If I am not wrong, a possible grammar could be
$S \to UTU +U$
$T \to 0T0 + 0T1 + 1T0 + 1T1 + U$
$U \to 0 + 1$