Shortest path with a fixed number of edges

Question

Find the shortest path through a graph in efficient time, with the additional constraint that the path must contain exactly n nodes.

We have a directed, weighte

Answer 1

Interesting problem. Did you discuss using a heuristic graph search (such as A*), adding a penalty for going over or under the node count? This may or may not be admissible, but if it did work, it may be more efficient than keeping a list of all the potential paths.

In fact, you may be able to use backtracking to limit the amount of memory being used for the Dijkstra variation you discussed.