Given a list of scores, find the second highest value (the runner-up). This tests your ability to track multiple values while iterating through a collection. You can't just find the max and subtract . If scores are [, , , , ], the max is but the runner-up is , not .
Duplicate maximum values shouldn't affect the result. Think about what you need to track. One approach: find the max, then find the max of everything except that value. Another approach: sort and deduplicate.