Tag · Algorithm

Catching Car Mileage Numbers


“7777…8?!??!“, exclaimed Bob, “I missed it again! Argh!” Every time there’s an interesting number coming up, he notices and then promptly forgets. Who doesn’t like catching those one-off interesting mileage numbers?

Let’s make it so Bob never misses another interesting number. We’ve hacked into his car’s computer, and we have a box hooked up that reads mileage numbers. We’ve got a box glued to his dash that lights up yellow or green depending on whether it receives a 1 or a 2 (respectively).

It’s up to you, intrepid warrior, to glue the parts together. Write the function that parses the mileage number input, and returns a 2 if the number is “interesting” (see below), a 1 if an interesting number occurs within the next two miles, or a 0 if the number is not interesting.