Lesson Review

In the previous lesson we learned about the Collection interface. In this lesson we learned about some additional, more advanced collections:

• Maps are collections that use key-value pairs, making it possible for us to find an element more efficiently (in constant time rather than linear time).
• Sets are collections that avoid duplicate elements.
• Queues are collections that support a First-In, First-Out order, so that we can process elements in the order they arrive.

These three collection types are very different from one another, but each of them provides a uniquely powerful data structure that, when used correctly, can solve complex problems efficiently.