M-Decoder is an online event spanning three days which will be open for 2 hours each day from 9:00 p.m. to 11:00 p.m. 

The participant can start the contest anytime within this time frame and will be allowed to play for 100 minutes from the start time until the portal has been closed.

The event will have three sections (Hard, Medium, and Easy). 

The participant will be directed to the Hard section at first, and the other sections remain locked. 

If the participant feels the need to shift to the next section (Medium), the Hard section can be locked, and one can move on to the Medium section. 

The same procedure applies to the transition from the Medium to Easy section. 

The participant with the most points at the end of the third day wins. 

Only one chance will be given to the participant on any particular day to go back from Easy to Medium or Medium to Hard, and this can be used only on one of the three days.

If you missed out on a day of participation, you could still solve the previous day's problems in the 2-hour period the next day. 

As you may expect, the scores will be reduced for those problems.

For further details about scoring, please visit the judging criteria. 

You can only see questions from the immediate previous day, i.e, you cannot see the 1st day's questions on the 3rd day.