February Challenge 2015
Chef and Strange Formula, Chef and Chain, Chef and Equality, Let us play with rank list
May Challenge 2015
Chef and Prime Divisors, Set Difference , Chef and new recipe
June Challenge 2015
Chef and Memory Limit, Chef and Polygons
October Challenge 2015
Rupsa and Equilateral Triangle, Who dares to be a millionaire, Count Subarrays, Time measure
December Challenge 2015
Chef and the stones, Plane Division, Oracle Devu and Longest Common Subsequence, Chef and Filters
January Long Challenge 2016
Rupsa and the Game, Churu and Balls, Devu and Perfume
September Challenge 2016
Chef and calculation, Faded Palindromes, Chef and digits of a number
November Challenge 2016
Count Permutations, Friends Meeting, Urban Development, Gift and Chef, Chef and squares, Task for Alexey
June Challenge 2017
Pairwise union of sets, Triplets, Xenny and Coin Rankings, Chef and the Feast, A Good Set
July Challenge 2018 Division 2
Magic Set, Strike or Spare, No Strings Attached
November Challenge 2018 Division 2
Chef and Ridges, Chef and Difficult Contests, Chef and Happiness
January Challenge 2019 Division 2
Different Neighbours, Lucky Number Game, Distinct Pairs, Fancy Quotes
Russia