Let's say I have collected a dataset for estimating algorithmic complexity:
where x is the input size and t is the elapsed time. This may be
O(1), O(logn), O(n), O(n^2), O(n^3) etc.. To find the closest class, it would be necessary to run a linear/non-linear regression to fit the data and find the curve of the best fit. However, that would be too time consuming.
My question is: is there a quick way to tell if the rate of growth is worse than O(n^2)?