#Sets A set is a collection of unordered elements that are unique it cannot contain duplicate values. Similar to a bubble it doesn’t know where they are, just knows that they exist there. regardless of how many elements are within whether it is 10000000 elements or 2 elements. As opposed to arrays the longer it gets the longer it will take to perform an operation within it There are three types of sets: HashSet: no particular order insertion: O(1) removal: O(1) contains: O(1) LinkedHashSet: insertion order insertion: O(1) removal: O(1) contains: O(1) TreeSet: sorted order insertion: O(n*logn) removal: O(n*logn) contains: O(n*logn) We use a set when we don’t care how many times something exists or where it exists. We use sets over arrays because it is faster and simpler to do operation on.