We study the point-to-point shortest path problem in a setting where preprocessing is allowed. We improve the reach-based approach of Gutman [16] in several ways. In particular, we introduce a bidirectional version of the algorithm that uses implicit lower bounds and we add shortcut arcs which reduce vertex reaches. Our modifications greatly reduce both preprocessing and query times. The resulting algorithm is as fast as the best previous method, due to Sanders and Schultes [27] . However, our algorithm is simpler and combines in a natural way with A * search, which yields significantly better query times.
Goldberg et al. REF proposed an efficient shortest path algorithm which combines with A * search.
Reach for A∗: Efficient point-to-point shortest path algorithms
IN WORKSHOP ON ALGORITHM ENGINEERING & EXPERIMENTS
Computer Science