We define the border array ba such that ba[i] is the longest border of x[1:i+1].
Implement a function, border_array(x) -> ba, that computes this border array.
Now, define bax such that bax[i] is the longest border of x[1:i+1] where x[bax[i]] differs from x[i+1], that is, the next character after the border and the position in x must be different. We call this the strict border array.
Can you derive an algorithm for computing bax? What is the running time?
Implement a function, strict_border_array(x) -> bax that computes the strict border array.
A hint here is that either bax[i]=ba[i], when the additional condition is satisfied, or else it must be the longest border of x[1:ba[i]] where the condition is satisfied (can you show why?). This is a value that can be found in bax.