In this paper, we consider a special type of triangular range search for a planar point set S in the I/O-model. Here, two sides of the query triangle are parallel to the coordinate axes (x- and y-axis). We call such a triangle an axis parallel triangle. For the axis parallel triangular range search problem, we propose a data structure of size O(N B ( log1+ B N logB logB N )2 ) disk blocks and a query algorithm of complexity O(logB N( logB N logB logB N )2 + K/B) I/Os, where 0 < < 1, N is the number of points in S, B is the number of points transferred in one I/O, and K is the number of points in the answer to the query. We also consider the application of this data structure and query algorithm to oriented rectangular range search.
Gautam K. Das, Bradford G. Nickerson