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Instructions

"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.

"Interesting" Numbers

Interesting numbers are 3-or-more digit numbers that meet one or more of the following criteria:

  • Any digit followed by all zeros: 100, 90000
  • Every digit is the same number: 1111
  • The digits are sequential, incementing†: 1234
  • The digits are sequential, decrementing‡: 4321
  • The digits are a palindrome: 1221 or 73837
  • The digits match one of the values in the awesome_phrases array
  • †For incrementing sequences, 0 should come after 9, and not before 1, as in 7890.
  • ‡For decrementing sequences, 0 should come after 1, and not before 9, as in 3210.

So, you should expect these inputs and outputs:

# "boring" numbers
is_interesting(3, [1337, 256])    => 0
is_interesting(3236, [1337, 256]) => 0

# progress as we near an "interesting" number
is_interesting(11207, []) => 0
is_interesting(11208, []) => 0
is_interesting(11209, []) => 1
is_interesting(11210, []) => 1
is_interesting(11211, []) => 2

# nearing a provided "awesome phrase"
is_interesting(1335, [1337, 256]) => 1
is_interesting(1336, [1337, 256]) => 1
is_interesting(1337, [1337, 256]) => 2

Error Checking

  • A number is only interesting if it is greater than 99!
  • Input will always be an integer greater than 0, and less than 1,000,000,000.
  • The awesomePhrases array will always be provided, and will always be an array, but may be empty. (Not everyone thinks numbers spell funny words...)
  • You should only ever output 0, 1, or 2.