November Challenge 2014
Chef and Words, Distinct Characters Subsequence, Let us construct palindrome, Chef and Segment Game
September Challenge 2015
Nikitosh and xor, Count Steps in Matrix
April Challenge 2016
Help Watson Escape, Chef and Ballons, Chef And Magical Path, Chef And Coloring
August Challenge 2016
Chef and Chocolate, Chef and Round Run
September Challenge 2016
Faded Palindromes, Chef and calculation, Chef and digits of a number, Chef and Friends
October Challenge 2017
Chef and a great voluntary Program, Max Mex, Counter Test For CHEFSUM, A Balanced Contest
March Challenge 2018 DIV 2
Pishty and Triangles, Chef and Easy Problem, A Big Sale, Mix the Colors, Chef and Glove, Minions and Voting, Minion Chef and Bananas
August Challenge 2018 Division 1
Coordinate Compression , Modular GCD
Belarus