Hey Tao, looking at this right now you're kinda right, the correct word should have been "approaches".

BTW the time complexity is not calculated by the number of weight elements. Instead its calculated as a combination of number of training iterations, "t" (represents by the arbitrary number 500 chosen in Fig.39), and the number of training examples, "m".

So the time complexity becomes:

O(tm)

As the number of training examples approaches the number of training iterations i.e. m -> t the Time complexity approaches polynomial time O(tm) -> O(t^2).