June Challenge 2017
Persistent oak, Chef and Prime Queries, Saboteur (Challenge), A Good Set, Cloning, Chef and the Feast, Xenny and Coin Rankings, Triplets, Pairwise union of sets
December Challenge 2018 Division 2
Chef and Interactive Contests, Chef and An Ideal Problem
April Challenge 2019 Division 2
Playing with Numbers, Friend or Girlfriend, Maximum Remaining
China