December 2009 (Contest XI)
Effective Sets, Palindromic Numbers, Maze of Digits, Plant Location, The N Queens Puzzle Revisited
January 2010 (Contest XII)
Circle of towers, Lost Primes
March 2010 Contest
Treasure Hunting, K-important Strings, The Best Tower, Tri-Hexagonal Puzzle
June 2010 Contest
Robot Game, Squirrel and chestnut
April Challenge 2016
Help Watson Escape, Chef and Ballons, Chef And Magical Path, Chef And Coloring
March Challenge 2018 DIV 2
A Big Sale, Mix the Colors, Chef and Glove
December Challenge 2019 Division 2
Plus Multiply, That Is My Score!
India