Time complexity of set in Java -

can tell me time complexity of below code?

a array of int.

set<integer> set = new hashset<integer>(); (int = 0; < a.length; i++) {     if (set.contains(arr[i])) {         system.out.println("hello");     }     set.add(arr[i]); } 

i think o(n), i'm not sure since using set , contains methods well. calling add method of set.

can confirm , explain time complexity of entire above code is? also, how space take?

i believe o(n) because loop on array, , contains , add should constant time because hash based set. if not hash based , required iteration on entire set lookups, upper bound n^2.

integers immutable, space complexity 2n, believe simplifies n, since constants don't matter.

if had objects in array , set, have 2n references , n objects, @ 3n, still linear (times constant) space constraints.

edit-- yep "this class offers constant time performance basic operations (add, remove, contains , size), assuming hash function disperses elements among buckets."

see here.