September Challenge 2016
Faded Palindromes, Chef and digits of a number
February Challenge 2017
Chef and His Apartment Dues
March Challenge 2017
Xenny and Alternating Tasks, Bear and Extra Number
April Challenge 2017
Dish Of Life, Bear and Row 01, Similar Dishes
May Challenge 2017
Chef and his daily routine, Courses in an university, Median of adjacent maximum numbers
June Challenge 2017
A Good Set, Xenny and Coin Rankings
September Challenge 2017
Minimum Good Permutation, Little Chef and Sums
October Challenge 2017
A Balanced Contest, Max Mex
November Challenge 2017
Chef goes Left Right Left, Periodic Palindrome Construction, Villages and Tribes
February Challenge 2018
Chef And His Characters, Permutation and Palindrome
May Challenge 2018 Division 2
Minimum Deletions, Xor Again
Bangladesh