Eliminates duplicates based on the given key function.
Eliminates duplicates based on the given key function. There is no guarantee which elements stay in case element two elements result in the same key.
maps elements to a key, which is used for comparison
Eliminates duplicates based on the given equivalence function.
Eliminates duplicates based on the given equivalence function. There is no guarantee which elements stay in case element two elements are considered equivalent. this has runtime O(n^2)
Groups elements given an equivalence function.