January Challenge 2015
Chef and Stones, Sereja and Votes, Gcd Queries, Sereja and Number Division 2
February Challenge 2015
Chef and Chain, Let us play with rank list, Chef and Equality
July Challenge 2015
Bread, Na2a and lucky stone, Chef and Cube
August Challenge 2015
Gravity Guy, Cooking Machine, Aditi and Magic Trick
October Challenge 2015
Who dares to be a millionaire, Count Subarrays
August Cook-Off 2015
Chef and the Wildcard Matching
March Challenge 2016
Palindromic substrings, maximize the sum, Chef And Special Dishes
July Challenge 2016
Andrash and Stipendium, Chefland and Electricity, Chef and Tetris
September Challenge 2016
Chef and digits of a number, Faded Palindromes, Chef and calculation
India