frew@mclean.com set-1

HashSet: countDuplicates  allCharsSame 

TreeSet: sortAndRemoveDuplicates  common H   atLeastOnce H  

You may find the following code snippets helpful:

return new ArrayList<Integer>(set); //convert a set to an ArrayList

Set<Integer> set = new HashSet<Integer>(nums); //convert an ArrayList to a HashSet
Authoring docs

Copyright Nick Parlante 2017 - privacy