I understand time can not be negative, but the "n" we put inside Big-O notation is input integer, right?
That input integer can be negative, so why don't we take 1st and 2nd quadrants?
2 Answers
Input value is not important here, only amount of elements is significant, and amount cannot be negative.
(in some cases we need to account for number magnitude also)
Big-O is not measured on the value of the input but rather on the size of your input.
In cases where your input is a number, what matters is the number of bits, not value. This is an often misunderstood issue with Big-O.
So you can't have negatives because it's a little hard to send something with negative size to a function.
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