An optimal algorithm for maximum two planar subset problem /spl lsqb/VLSI layout/spl rsqb/

Abstract

The Two Row Maximum Planar Subset (TRMPS) problem asks for finding the maximum planar subset of nets, that can be routed between two rows of terminals an a cell row. This problem was first encountered by Gong, Liu, and Preas (1990). They declared it open, and presented an approximation algorithm for this problem. In this paper we show that TRMPS problem can be solved optimally in polynomial time, and we present an O(kn/sup 2/) algorithm to solve this problem. Our algorithm can also be extended to solve the TRMPS problem, in the presence of pre-routed nets, a chosen subset of nets, as well as for planar channel routing. We also apply our technique to obtain an improved approximation algorithm, for over the cell routing in middle terminal model standard cell layouts.<>