My rating decreased instead of increasing

Yesterday when the long challenge ended I noticed that my rating dropped instead of increasing whereas I have successfully submitted two problems, why is that happening?

The rating on codechef works in odd ways.
Basically codechef calculates your expected rank based on your current rating and the current rating of everyone else who participated.
So if your rank in the competition (10767) was worse than the expected rank then your rating will go down.

@dungeonmaster3 - the system has an ‘expected rank’ in mind when you participate in any contest. If you perform poorer than the expected rank, then your rating will drop. In this case - you solved 2 problems - while others with a similar rank probably solved more. Hence the rating dip.
You can check out others ranks here - CodeChef