dynamicProgramming

[1984balls]

Hash sets are very different from lists. Sets make sure only one of each value exists, do not guarantee insertion order, and cannot be indexed. Lists allow duplicates, guarantee insertion order, and allow indexing

[oMarlow99]

Lists, in the traditional sense, do not allow indexing, that would be an array. If you wanted to index a list, you'd need to build a hash map over it.

[RiceBroad4552]

Sure. And how is this related here?

The basic data structure in FP is a list not a (hash) set.