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kotlinlang

Generally speaking... running

`listOfIds.contains(this.id)` will run slower than `setOfIds.contains(this.id)` right?

Searching a list is O(n), whereas a set lookup is O(1).

on the other hand, a set takes a bit more memory and may take significantly more time to construct, especially if you have very deep structures of `data class`es and other containers (as `hashCode()` isn't by default (and can't generally be) cached)

if you already have a list, and you are only checking one element for membership _once_, then there is zero purpose to converting the list to a set first

if any of those preconditions change, then a set may be a better idea

Cool. That's roughly where my mind was at as well, but wanted a sanity check