[chrisseaton]

> This means is a magnitude faster than the previous one!

Is this right? It's a quadratic not an order of magnitude difference isn't it? And can you be an order of magnitude faster in an O notation expression anyway? Isn't an order of magnitude a coefficient? Don't we drop coefficients in O notation?

[asdginioubnou]

It's definitely wrong. A lot of people use "order of magnitude" to just mean "a lot".

I always use the precise meaning. It might be better for me to say "factor of ten" rather than "order of magnitude" if other people don't always use the precise meaning.

[fancyfredbot]

It's not wrong! For some value of N it is an order of magnitude faster. It's just a bit misleading.

[eesmith]

For another value of N it's three orders of magnitude faster.

In the example case where s[0] == s[1], it might be an order of magnitude slower, if there's much object initialization for the lookup table.

[stellalo]

> Is this right?

It's not right, indeed