What data structure is best suited for storing unique elements without duplicates?

To store unique elements without duplicates, it is best to use a data structure called "set" (Set). In Android (Java/Kotlin), this can be HashSet or LinkedHashSet.

A set automatically ensures the uniqueness of elements and allows efficient checking for the presence of an element, as well as adding and removing it.

Example in Kotlin:

val uniqueItems = mutableSetOf<String>()
uniqueItems.add("apple")
uniqueItems.add("banana")
uniqueItems.add("apple") // will not be added again
println(uniqueItems) // Outputs: [apple, banana]