December Challenge 2015
Plane Division, Chef and the stones
February Challenge 2016
Chef and Strange Operations, Devu and a light discussion, Rectangles of Love, Chef-Detective, Matrix Maximum Sum, Sereja and Two Lines
March Challenge 2016
Sereja and Two Strings 2, Palindromic substrings, maximize the sum
April Challenge 2016
Chef and Ballons, Chef And Coloring
June Challenge 2016
Chef and Rectangle Array, Devu and an Array, Chef and cities, Chef and Coins Game, Chef And Binary Operation, Chef and Array and K, Chef And The Hiring Event
July Challenge 2016
Andrash and Stipendium, Chef and Segments, Chef and Tetris, Chef and Robots Competition, Chefland and Electricity
August Challenge 2016
Chef and Chocolate, Chef and Round Run
September Challenge 2016
Chef and Friends, Dividing Machine, Chef and digits of a number, Faded Palindromes, JosephLand, Chef and calculation
January Challenge 2017
Chef and Circle, Tourists in Mancunia, Reservior, Digits Cannot Separate, Fantastic Four, Sereja and BOX, Sereja and Circles, Cats and Dogs, Capital Movement
March Challenge 2017
Cooking Schedule, Completing favorite game, Sum of distances, Xenny and Alternating Tasks, Pishty and birthday, Bear and Extra Number, Bandwidth of a matrix
India