Suppose the only thing you know is that your algorithm runs in O(n^2) time in the worst case. From this very fact you know that the upper bound looks like Cn^2 for some C > 0. Thus you know how the upper bound of your algorithm scales, namely, if you double the input size the upper bound quadruples.

Question: What practical question can you answer if you know the way the upper bound scales? I just can't understand if this particular knowledge is helpful in some way.

CodePudding user response：

If you know of an alternative algorithm that is not in O(