Yellow check mark (special correction blah..blah..)

[Joseph Kurniawan]

Anybody know what that means ?

[Krzysztof Duleba]

I'm not sure what you mean.

[UFP2161]

Usually means that there are potentially several correct solutions to a problem, and that any one of them will do, and the program they wrote will check that your answers are indeed correct, or something along those lines..

[Joseph Kurniawan]

But in prob 453 - INtersecting Circles, there is only one correct answer for every set of input, and yet the problem has yellow check mark????

[UFP2161]

Since it's a floating point problem, it's probably to give a +/- some epsilon to the answer, so it's not too strict.

[Joseph Kurniawan]

What's epsilon? I don't understand
I'm new to these kind of stuff. I'm 18 this year and have just learned in uni. I first learn these kind of stuff (computer language) one year ago (Last Sept 2002 to be precise). Before that I only know how to operate Microsoft Winword and play games. I don't even know how to operate Excel, Powerpoint ,etc.

[UFP2161]

Oh, epsilon in mathematics is usually used to refer to a very very tiny number, and generally, in computer science 10^-6 or 10^-9 is generally considered an appropriate +/- error for floating point numbers.

So, one could say that a number 1.000000 is more or less the same as 0.999999 or 1.000001 when you are using floating point numbers. That is, there is some margin of error that the special correction program allows.

[Joseph Kurniawan]

Thanks UFP2161, that clears the whole things up now!!!