This paper deals with problems on non-oriented edge-colored graphs. The aim is to find a route between two given vertices and . This route can be a walk, a trail or a path. Each time a vertex is crossed by a walk there is an associated non-negative reload cost , where and denote, respectively, the colors of successive edges in this walk. The goal is to find a route whose total reload cost is minimum. Polynomial algorithms and proofs of NP-hardness are given for particular cases: when the triangle inequality is satisfied or not, when reload costs are symmetric (i.e., ) or asymmetric. We also investigate bounded degree graphs and planar graphs. We conclude the paper with the traveling salesman problem with reload costs.
A preliminary version appeared in the proceedings of the 35rd International Conference on Current Trends in Theory and Practice of Computer Science (SOFSEM 2009), LNCS 5404 Springer 2009, 621–632.