June Challenge 2013
Collecting Magical Berries, Just Some Permutations 3, Dessert Wizard, Two k-Convex Polygons, Count Special Matrices, Predictopus, To challenge or not, W String, Lapindromes, Little Elephant and Mouses
December Challenge 2013
Reign, Query on a tree VI, Rectangular Queries, Magic Pairs, Funny Marbles, Chef and Codes, Lucy and the Flowers, Cube Cakes, Art in Digital Age, Petya and Sequence
January Challenge 2014
ForbiddenSum, Chef and Feedback, Please like me, Bon Appetit, Byteland Tours, Meteor, Counting D-sets, Sereja and Graph, Counting The Important Pairs, Magic Trick
April Challenge 2014
Final Battle of Chef, Shortest Path in Binary Trees, Divide the Tangerine, Chef and Digits, Farmer Feb, Counting Matrices, Cards, bags and coins
May Challenge 2014
Little Elephant and Balloons, Sereja and Game, Compilers and Parsers, Dynamic Trees and Queries, Chef-jumping, Fun with AGp, Sereja and Subsegment Increasings, Chef and Strange Matrix, The Malaysian Flight Search, Stone
May Lunchtime 2014
Approximately II, Brand New Game, Roots of a Tree
April Challenge 2015
Count Sequences, Chef and Array, Chef and Interview, Broken Telephone, Inversion sorting, Division of Lands, Chef and Piano Scales, Little Party, Black-white Board Game, Devus and their voting system
China