I see where you're coming from and we're probably getting wayyy in the weeds on this...:)....but I think they mean an insert of item into already existing array is O(1) and from your perspective ..traversal over time would be O(n) so I think y'all might both correct from diff perspectives.

I was thinking increasing insert time would increase Big O but they made the point that it's a constant which will cancel out as n approaches infinity.

God I'm a nerd.