Digit search
This is one of those weird programming puzzles with no real point except practice. But it's considered Very Hard in JavaScript. Let's see how we do in Clojure.
Write a function that takes a sequence of integers. You're trying to get all 10 digits by looking through the numbers sequentially. When you have found one instance of every decimal digit, return whatever number you were on when you found the last one. If you get to the end of the sequence without finding all the digits (for instance, maybe there was no 9
), then just return nil
.
Example
(digit-search [5175 4538 2926 5057 6401 4376 2280 6137]) ;=> 5057