Too much domain knowledge for an IDE to catch. I'm self taught as well, and it comes down to spending more time thinking about the code than writing the code.
It's a fairly simple thought experiment to ask yourself what if there was 10x items in this array? 100x? That is essentially what the O(n) notation is trying to quantify. You just don't need to do it that formally.
It's a fairly simple thought experiment to ask yourself what if there was 10x items in this array? 100x? That is essentially what the O(n) notation is trying to quantify. You just don't need to do it that formally.