The Lee algorithm is one possible solution for maze routing problems based on breadth-first search. It always gives an optimal solution, if one exists, but is slow and requires considerable memory.
Algorithm Initialization
Select start point, mark with 0 i := 0 Wave expansion
REPEAT Mark all unlabeled neighbors of points marked with i with i+1 i := i+1 UNTIL ((target reached) or (no points can be marked)) Backtrace
go to the target point REPEAT go to next node that has a lower mark than the current node add this node to path UNTIL (start point reached) Clearance
Block the path for future wirings Delete all marks Of course the wave expansion marks only points in the routable area of the chip, not in the blocks or already wired parts, and to minimize segmentation you should keep in one direction as long as possible.
External links http://www.eecs.northwestern.edu/~haizhou/357/lec6.pdf
References Wolf, Wayne (2002), Modern VLSI Design, Prentice Hall, pp. 518ff, ISBN 0-13-061970-1 Lee, C. Y. (1961), "An Algorithm for Path Connections and Its Applications", IRE Transactions on Electronic Computers, EC-10 (3): 346–365, doi:10.1109/TEC.1961.5219222, S2CID 40700386 Rubin, F (1974), "The Lee Path Connection Algorithm", IRE Transactions on Electronic Computers, C-23 (9): 907–914, doi:10.1109/T-C.1974.224054, S2CID 32651989 Remzi Osmanli