And can garbage collect all N levels of the trees using N empty flash memory blocks. The algorithm is exponential time in the worst case, but the worst case is rare and the algorithm requires reserving only a handful of flash-memory blocks.
And can gather all N levels of the trees using N vacant flash memory blocks. The algorithm's efficiency is exponential in its worst-case scenario; however, this situation is unusual, and the algorithm requires reserving only a small amount of flash-memory space.