A Turing machine is an abstract machine that manipulates symbols on a strip of tape according to a table of rules; to be more exact, it is a mathematical model of computation that defines such a device. (Wikipedia)
Now the question is :
Design a Turing Machine which finds center of a given string with even length.
Note : For example if the given string is $w=a_1a_2\dots a_na_{n+1}\dots a_{2n} \space\space\forall i \space a_i\in \Sigma$, then the turing machine returns $w'=a_1a_2\dots a_nca_{n+1}\dots a_{2n}\space\space c\in\Gamma-\Sigma$ where $\Sigma$ is the alphabet and $\Gamma$ is the Stack Alphabet ( often called tape alphabet ).
Thanks in advance.
Best Answer
A general strategy could be something like: