i think there is problem in system since long challenge of feb (FEB16) some of the previous contest i.e ZCO and IOI 2016 are running now may be you can’t see but i do.
in FEB16 some member has reported you to take care of submission of call center scheduling problem that was visible to some user,
please take care of it. i have included some pictures and one video for proof my dropbox:- https://www.dropbox.com/sh/dddct78t4flahrj/AAC8DlxZTJ7S3ex4S-_CHOsia?dl=0
May be it is just for the school students who want to practice for ZCO and INOI. These contests will help them to test their own codes. It is really tough to find a particular problem from the practice section. These contests will help them to find all the past problems easily.