February 2012 Challenge
Word Couting, Count of Maximum, Lucky Long
March Challenge 2013
Tourist Translations, Approximately
November Challenge 2014
Chef and Segment Game, Distinct Characters Subsequence, Chef and Red Black Tree, Let us construct palindrome
January Challenge 2015
Chef and Stones, Gcd Queries, Sereja and Votes
April Challenge 2015
Chef and Interview, Broken Telephone
September Challenge 2015
Chain of Doughnuts, Count Steps in Matrix, Lighthouses
October Challenge 2015
Rupsa and Equilateral Triangle, Spheres, Count Subarrays, Time measure, Who dares to be a millionaire
November Challenge 2015
Receipt Recovery, Chef and collection of stamps, Eugene and function, Simple Sum, Chef and cakes
December Challenge 2015
Chef and the stones, Plane Division
May Challenge 2016
Chef and Balls, Laddu, Chef and Big Soccer, Forest Gathering
June Challenge 2016
Chef And The Hiring Event, Chef And Binary Operation, Chef and Coins Game, Devu and an Array
April Lunchtime 2016
Maximum K Sums, Coins And Triangle
March Challenge 2017
Xenny and Alternating Tasks, Bear and Extra Number, Bandwidth of a matrix
Indonesia