October Challenge 2017
A Balanced Contest, Max Mex
January Challenge 2018
K-Concatenation, Maximum Score, Rectangle
February Challenge 2018
Chef And His Characters, Chef And The Patents, Car-pal Tunnel, Permutation and Palindrome
March Challenge 2018 DIV 2
A Big Sale, Chef and Glove
April Challenge 2018 Division 2
Weight of Numbers, Workers, Average of Pairs
September Challenge 2018 Division 2
Magician versus Chef, Chef and Adventures
December Challenge 2018 Division 2
Chef and Interactive Contests, Chef and An Ideal Problem
February Challenge 2019 Division 2
Chef and Secret Ingredients, Appy and Contest
September Challenge 2019 Division 2
Easy Fibonacci, Chef and Interesting Subsequences
India