Why is it better to create a TreeSet from a HashSet instead of creating a new TreeSet and adding elements to it?

Question

Hello,
I was reading about Collections in Java and I found this information: "It is generally faster to add elements to the HashSet and then convert the collection to a TreeSet for a duplicate-free sorted traversal."
I know that the time complexity for inserting, removing, etc. in HashSet is O (1) and in TreeSet is O (logn) for the same operations, but don't we pay for the TreeSet insertion anyway when creating the tree?

Answer 1

Hi,

That is an interesting question.
Yes, you pay a price for using a TreeSet over a HashSet, but this overhead is well justified when there is a natural ordering in place.

Here's my code for your reference.

https://code.sololearn.com/c4hhhyD5ji7c/?ref=app

Hope that helps.

Chris