May Challenge 2014
Sereja and Game, Compilers and Parsers, Chef-jumping, Chef and Strange Matrix, Stone, Little Elephant and Balloons
December Cook-Off 2016
Chef and Subset, Chef and Subarrays
June Challenge 2017
Pairwise union of sets, Triplets, Xenny and Coin Rankings, Chef and the Feast, Cloning, A Good Set, Euler Sum, Saboteur (Challenge), Chef and Prime Queries
Sweden