Abstract
We propose an algorithm to find the lowest-fare path between two specified stations in the JR-EAST area where the IC-card ticket will be available in 2007. The lowest-fare path is sometimes different from the shortest path, because JR-EAST has many exceptional calculation rules in addition to the four calculation-tables used for the three specified areas and two kinds of lines, i.e. the main line and local line. Our algorithm solves at most only four shortest path problems for the fare between two specified stations, although it can deal with the complex situation mentioned above. Therefore the algorithm can calculate fares between all pairs of stations not only very quickly but also exactly.
