September Challenge 2016
Chef and digits of a number
November Challenge 2016
Chef and squares, Task for Alexey
February Challenge 2017
Chef and His Apartment Dues
May Challenge 2017
Chef and his daily routine, Courses in an university, Blocked websites, Median of adjacent maximum numbers
June Challenge 2017
Xenny and Coin Rankings, A Good Set
July Challenge 2017
Chef and Sign Sequences, Whats in the Name
August Long Challenge 2017
Chef and Rainbow Array, Chef and Mover, Palindromic Game, Greedy Candidates
October Challenge 2017
Max Mex, A Balanced Contest
July Cook-Off 2017
Chang and the Perfect Function, Chang and Bitwise OR
August Lunchtime 2017
Mathison and the Dynamo shuffle, Mathison and pangrams
January Challenge 2018
K-Concatenation, Maximum Score, Rectangle
April Challenge 2018 Division 2
Workers, Average of Pairs, Count Good Prefixes, Highway Crossing, Weight of Numbers, Chef and Array (Challenge)
September Challenge 2018 Division 2
Magician versus Chef, War of XORs, Chef and Adventures, Table Game, Bad Shuffle
October Challenge 2018 Division 2
Appy and Balloons , Chef and Serves, Byte to Bit
India