An O ( n log n ) algorithm for maximum st -flow in a directed planar graph
Glencora Borradaile, Philip N. Klein · Journal of the ACM · 2009
We give the first correct O ( n log n ) algorithm for finding a maximum st -flow in a directed planar graph. After a preprocessing step that consists in finding single-source shortest-path distances in the dual, the algorithm consists of repeatedly saturating the leftmost residual s -to- t path.