We study the point-to-point shortest path problem in a setting where preprocessing is allowed. We improve the reach-based approach of Gutman in several ways. 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 competitive with the best previous method, due to Sanders and Schultes. However, our algorithm is simpler and combines in a natural way with A* search, which yields significantly better query times.

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In: SIAM Workshop on Algorithms Engineering and Experimentation (ALENEX 06)

Publisher: Society for Industrial and Applied Mathematics
Copyright © 2007 by Society for Industrial and Applied Mathematics.

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