The Pony Express was a mail service operating in the US in 1859-60.
It reduced the time for messages to travel between the Atlantic and Pacific coasts to about 10 days, before it was made obsolete by the transcontinental telegraph.
There were a number of stations, where:
- The rider switched to a fresh horse and carried on, or
- The mail bag was handed over to the next rider
stations is a list/array of distances (miles) from one station to the next along the Pony Express route.
Implement the riders method/function, to return how many riders are necessary to get the mail from one end to the other.
NOTE: Each rider travels as far as he can, but never more than 100 miles.