I assumed that "sequence is very long" meant "the time (and space?) complexity of your solution matters". Iterating over the sequence x times doesn't change th

I assumed that "sequence is very long" meant "the time (and space?) complexity of your solution matters". Iterating over the sequence x times doesn't change the time complexity, so long as x << n (i.e. it's O(n) whether x is 1, 2 or 3). Unfortunately, revealing whether my assumption proved correct would give away how they assess the solution to this demo problem, which some might view as a spoiler. EDIT: since people are posting actual solutions, I suppose mere analysis of the testing methodology is okay. My assumption was correct.