Edit (Jan 22, 2:45 AM UTC): Added Div1E and the editorial is now complete. I am sorry for the delay.
Edit (Jan 21, 9:45 AM UTC): Added the explanation for Div1C/2E, and the problem setters' codes. Div1E will need several more hours. Thank you again for your patience.
First, here are some statistics on this round:
|Division||Registrants||Participants||A Accepted||B Accepted||C Accepted||D Accepted||E Accepted|
|(Estimated number of AC by me)||800 (wrong)||500 (wrong)||70 (FAIL)||90 (ok)||5 (wrong)|
We are sorry for terribly underestimating the difficulty of the problems (except Div1D), especially Div1A/2C and Div1C/2E.