Your solution is not good. Every good boy just use O(1) memory and O(n) time, you use O(n) memory.

Good work!

good work!

In the example there is a little typo = should be ==

To clarify , == (equality operator) in JavaScript will convert types when comparing.

For example, return 5 = '5' will return true even though it is comparing a number and a string.
This is because JavaScript will convert them to the same type when comparing.

Using === (strict equality operator) will not convert type so the above example would return false

== is never enough. == bites. == is inexplicable bugs waiting to happen.

=== is much more predictable and untemperamental.