distance
The number of edges on the shortest path between this node and other.
Computed as depth() + other.depth() - 2 * lca.depth(), where lca is their lowestCommonAncestor. The distance from a node to itself is 0.
Return
the edge count, or null when the two nodes belong to different trees.
Runs in O(da + db) time, where da/db are the depths of the two nodes.
Parameters
other
the other node to measure the distance to.