Compress all Subsegments

For an array $B$, while it has more than one element, you can apply an operation on it - you choose any two elements $x,y$ (they may be the same value, but they should have different indices), delete them, and add an element $g(x, y)$ instead. Here $g(x, y)$ denotes the highest set bit in $x \oplus y$, or $0$ if they are equal. In other words, $g(x, y) = \max 2^k$, such that $2^k \leq (x \opl