For this weekend's contest, we will have a taste of regional round.
Codeforces has practice contests similar to regionals in their gym at
http://codeforces.com/gyms. The next contest of this year (named S02E02) will be released tomorrow at 5:40 pm. It will be a 4.5 hour contest, and you can participate in teams!
To create teams on Codeforces : On your profile page, there is a tab named "Teams". Go there and create a new team.
A things to notice : First see the input/output method on the contest Dashboard (e.g., Dashboard of S021E01 at
http://codeforces.com/gym/100484). Most of the time it is standard input/output (usual cin/cout etc work), but sometimes they ask to do that via files, like at
http://codeforces.com/gym/100283. In that case put first thing inside your main function :
freopen("inputFileName.in","r",stdin);
freopen("outputFileName.out","w",stdout);
whichever is necessary. After that usual cin/cout etc will work.