This problem involves determining the number of routes available to an emergency vehicle operating in a city of one-way streets.
本问题是要来计算：在一个所有街道都为单行线的城市中，一辆急救车可以通行的路径的数量。
2
The routing algorithms are employed in determining the proper routes along which the information packets input at a node of a computer network are transmitted so that the specified costs are minimum.