Merging RLBWTs adaptively

We show how we can merge two run-length compressed Burrows-Wheeler Transforms (RL-BWTs) into a run-length compressed extended Burrows-Wheeler Transform (eBWT) in $O (r)$ space and $\tilde O(r + L)$ time, where $r$ is the number of runs in the final eBWT and $L$ is the sum of the longest common prefix (LCP) values at the beginnings of those runs.