May Challenge 2018 Division 2
Minimum Deletions, Xor Again, Dibs on Fibs, Mighty Friend
December Challenge 2018 Division 2
(Challenge) Delete DAG, Max and Electrical Panel, Directing Edges, Chef and Interactive XOR, Chef and Meatballs, Chef and Interactive Contests, Chef and An Ideal Problem
February Challenge 2019 Division 2
Chef and Magical Jars, Deputy Chef, Art of Balance, Appy and Contest, Chef and Secret Ingredients
July Challenge 2019 Division 2
Guess the Prime!, Parity Again, Codechef War, Circular Merging, Minimum and Maximum, Chef and Mean
Taiwan