Depends on method for finding augmenting path.
Use breadth-first search (Edmonds-Karp Algorithm). Thus, the augmenting
path is shortest from s to t.
The total number of augmentations is ? O(VE) , ? O(E) per
augmentation. Thus the algorithm has run time O(VE2).
Preflow-Push method yields O(V2E) (Section 27.4), and
Lift-to-Front method yields O(V3) (Section 27.5).