This problem taught you how pairs group related values. Instead of two separate arrays for occupancy and capacity, you store them together. This prevents index mismatches and makes your code clearer.
I showed you filtering with conditions. You loop through a collection and count items that meet a requirement. This pattern works when you need to find how many elements satisfy a property.
You learned that simple problems benefit from proper data structures. Pairs make your intent clear: these two values belong together. When you see a relationship between data points, use pairs or tuples.