This package provides a reference implementation of my skew binary random
access algorithm for performing an /online/ lowest common ancestor search (and
online level ancestor search) in logarithmic time without preprocessing.
This improves the previous known asymptotic bound for both of these problems
from /O(h)/ to /O(log h)/, where /h/ is the height of the tree. Mostly
importantly this bound is completely independent of the width or overall size
of the tree, enabling you to calculate lowest common ancestors in a distributed
fashion with good locality.
While /offline/ algorithms exist for both of these algorithms that that provide
/O(1)/ query time, they all require at least /O(n)/ preprocessing, where /n/ is
the size of the entire tree, and so are less suitable for LCA search in areas
such as revision control where the tree is constantly updated, or distributed
computing where the tree may be too large to fit in any one computer's memory.
Slides are available from