Develop and test an implementation of the augmenting-path method that is based on alternately growing search trees rooted at the source and at the sink (see Exercises 21.35 and 21.75).
Exercises 21.75
Develop a class implementation for the source-sink shortest-paths problem in Euclidean graphs that is based on the bidirectional search described in Exercise 21.35.
Exercise 21.35
Develop a class for the source-sink shortest-paths problem that is based on code like Program 21.1 but that initializes the priority queue with both the source and the sink. Doing so leads to the growth of an SPT from each vertex; your main task is to decide precisely what to do when the two SPTs collide
