870A - Search for Pretty Integers Idea, preparation, editorial komendart

870B - Maximum of Maximums of Minimums Idea DPR-pavlin, preparation, editorial mHuman

870C - Maximum splitting Idea, preparation, editorial komendart

870D - Something with XOR Queries Idea, preparation, editorial mHuman

870E - Points, Lines and Ready-made Titles Idea, preparation, editorial komendart

870F - Paths Idea, preparation komendart

871E - Restore the Tree Idea MikeMirzayanov, preparation fcspartakm

Also many thanks to coordinator KAN, testers ifsmirnov, vintage_Vlad_Makeev, AlexFetisov and any other people who participates in preparation of contest.

Code (C++) 31365874

Code (Python) 31365844

Code 31366254

Code 31365909

Code 31366223

Code 31365959

Code 31366002

Code 31368704